If the spoken sound is the same, I assume the meaning comes from context. Are the written adornments therefore redundant? Is it much like English how we now have knight and night?
There is a poem that illustrates it, where each syllable is pronounced exactly the same, /shi/ just with different tones: https://en.wikipedia.org/wiki/Lion-Eating_Poet_in_the_Stone_... (施氏食獅史). It goes like that:
« Shī Shì shí shī shǐ »
Shíshì shīshì Shī Shì, shì shī, shì shí shí shī.
Shì shíshí shì shì shì shī.
Shí shí, shì shí shī shì shì.
[...]
According to google translate though, the tones on the parent example are identical. So context would be all they have to go by unless there is an aspect I'm missing as a non-speaker.
It's probably the case that reading is just harder for us to process than listening in general which is why jokes like http://guidetogrammar.org/grammar/twain.htm exist. We hold onto a lot of redundancy too in the English world.
> Fainali, xen, aafte sam 20 iers ov orxogrefkl riform, wi wud hev a lojikl, kohirnt speling in ius xrewawt xe Ingliy-spiking werld.
The first "a" in "Fainali" is not pronounced the same as the second "a" in "Fainali" (e.g. finally does not rhyme with rally and rawly, the correspondence between the latter two depending on your own regional accent). The "x" in "xen" and "xe" is not the same sound as the "x" in "xrewawt" or in "orxogrefkl." The "o" in "lojikl" is not the same "o" as in "kohirnt." The "e" in "xe" is not the same "e" as in "xen" and is not the same "e" as in "orxogrefkl." And more.
And that's not even touching stuff that has heavy regional variation such as the "e" in "aafte" and the "i" in "kohirnt."
In spoken Mandarin, lexical units are generally formed of multiple-character compounds (typically 2 to 4 characters). In such a scenario, the character being used can be figured out just from the context. If such an utterance is transcribed phonetically and written down, the same still holds. So your conjecture is correct to the extent it pertains to the colloquial language.
However, the same cannot be said for the formal written language, which is based on Classical Chinese, and much more succint: here, each character is often an independent lexical unit. At the same time, numerous more obscure characters come into play and annoyingly many of them tend to be homophones. In particular, in Mandarin, as a result of the phonetic processes it underwent, there are a lot of characters pronounced either /yi/ or /shi/.
At this point, figuring out the meaning of what is being said tends to become cumbersome or downright impossible (as in the case of the poem), unless the actual written characters can be seen, which is usually not an issue as this form of the language is used predominantly in writing (with the exception of a huge number of idiomatic expressions that educated people are expected to know by heart and be accustomed to).
And it is this latter form of Chinese that is the language of history, culture, but also anything more sophisticated in general, such as any better news publications. So while a basic, dumbed-down version of Mandarin would survive even when simplified even further, perhaps to the point of being written only phonetically, I doubt any educated Chinese would willingly sign up for it (particularly as there are is no incentive to do so since everybody learned the language as a child anyway, and for those who did it well, it is a marker of status).
If you want the Chinese to ditch their "written adornments," you could just as well be telling them to switch to Esperanto.
That is to a large extent the "meaning" of the orthography is irrelevant to the spoken language.
I could come up with an alternative highly differentiating orthography for e.g. French without considering its spoken language either. I could mandate that "suis" as in "être" is not spelled "suis" but rather "swi" and "suis" as in "suivre" is still spelled "suis," but that has absolutely no impact on the spoken language. There is no difference to a speaker between a world where we have "swi" and "suis" and a world where we have two meanings of "suis."
Separately, it's also important to realize that Chinese characters don't always correspond to words in the same way that happens in English. From an English perspective, it is easier to think of Chinese characters in modern Mandarin as individual morphemes [0], e.g. stuff like prefixes and suffixes, that are also sometimes standalone words, rather than always entire words themselves.
So for example 誠 is not a standalone word in the same way "hono-" (e.g. "honesty," "honor," etc.) is not a standalone word in English, even though it is a recognizable prefix that means something.
So when spoken, speakers rely on a combination of audio and context cues to disambiguate the meaning and how word segmentation is supposed to be done (in the same way that English speakers both are able to distinguish between "knight" and "night" as well as "prototype" and the non-existent words "pro totype"). Note that this is subtly different from "disambiguating among characters." A less literate Chinese speaker might think that in fact 成, 誠, 城 are all a single character 成 that can be used in different ways when used as prefixes/suffixes in different words and we would have no way of knowing that without testing the speaker's writing capabilities.
Classical Chinese, the written, formal Chinese language from ~2500 years ago to ~100 years ago, however, where individual characters can almost always be used as standalone words, does present an interesting challenge when pronounced with a modern Mandarin pronunciation due to the high number of homophones in modern Mandarin (among characters but not words!). It can be very difficult to understand long tracts of Classical Chinese if it's spoken aloud using modern Mandarin.
This makes Classical Chinese essentially a written-only language. And in fact other systems for pronouncing Classical Chinese exist in countries that used it for writing but did not use Chinese for speaking (e.g. Japan, Vietnam, and Korea). This led to an interesting situation where literate individuals from those countries could communicate in writing with one another but not verbally.
[0]: This is a simplification. Despite many articles to the contrary, it is not true that all Chinese characters are morphemes. There are some rare cases of multi-character words whose constituent characters have no individual meaning and cannot be used outside of that single word.