That said, the characters are a whole boatload of unnecessary extra effort, and as a student of the two languages, the artificial illiteracy created by kanji, where I often just can't read words I've known for years, is simply maddening. Not having to wrestle with characters does free up a lot of time for both native and foreign students alike.
Yes, it's probably the worst since even Microsoft until now still struggle to provide proper search solution for Japanese names in their Windows OS due to their multitude of writing systems.
By sheer wills of course you can make everything hard feasible but that does not means it's efficient and effective. I consider Japanese as a unique country with extraordinary people that can collectively overcome adversity, that's include a non intuitive and difficult writing systems.
If your mother tongue is Korean (e.g Korean American) that only just started learning, it only take one day turnover from illiterate to literate.
How many Korean-Americans know the Korean words for things like 'legislature', 'inflation', or 'geopolitical tensions'?
But it is a complete non-sequitur to lead to the modern idea that English isn't phonetic.
Also, the same English word can be read in very different ways by the same speaker, but in different contexts. This is most proeminent with some of the most common words in English - a, the, there, and many other connective words can be pronounced very differently by the same speaker in the same speech, depending on stress (for example "a" can be pronounced as either ə if unstressed or eɪ if stressed). And yet, there is no version of written English that differentiates these - another sign that English is not a phonetic spelling.
Of course, on the other hand, you can't say that there is no correlation between spelling and pronunciation, like you can in Mandarin and other Chinese languages.
Nobody that knows how to read English at a level to be on an internet forum is surprised that English has odd spelling. Many people would be deeply confused to be told that written English doesn't follow a phonetic system. Rightfully so.