Phonics is not about "teaching English" in some fuzzy generic sense, it's specifically aimed towards teaching English written orthography, starting from its phonetics. I.e. teaching fluent speakers of English to read.
I could also see it resulting in more subvocalization, but my assumption is that subvocalization is actually a very important short-term strategy that almost always goes away quickly.
Individual letters don’t have sounds, but trigrams do.
food, good
rough, dough
two, to, too
If you go read old documents, you'll note they spelled English much more phonetically .
It's a fairly modern thing to use these standardized spellings
English is fairly phonetic. There's a few options for each phoneme and a few common words, but the vast majority follow obvious phonetic structures.
Calling English "fairly phonetic" is laughable. In most languages, they don't have spelling bees because they don't understand the concept. How would you not know how to spell the word after someone speaks it?