That is trivia that is useless in almost all contexts. I've been a native English speaker all my life and this is the first I've heard of that. I can't think of any situation in life where knowing that fact would have been helpful. Your claim seems reasonable, but if someone says you are wrong I wouldn't fact check it even if clear links were posted so that I could.

Im a materials scientist and I use etymology every day.

Knowing etymology is a an easy way to memorize things.

If you’re seeing a word for the first time, it is pretty useful - partly with pronunciation but definitely with meaning.

You do have to have some familiarity with the source languages, but if it’s an unfamiliar but nativized word, those are almost always ultimately Latin or Greek.

If you're seeing the word for the first time and need to figure out how to pronounce it, how would you know that “y” is acting as a vowel and not as a consonant in the first place?

If it's followed by a vowel, it's likely a Germanic word: yule, your, young, yellow (and you probably know the word, since our core vocabulary is still mostly Germanic). If it's at the end or between consonants, like syllabary or ontogeny, probably Greek.

You might also just happen to know a smattering (or even a lot) of Greek and Latin.

But if you had known it (aka, if anyone had taught it to you), it wouldn't be useless, as you would know the context and how to pronounce it...not to mention the meaning behind it

For sure, but I'm not sure this the primary purpose of a writing system.

By all means a fun aspect about English that you can look at a word and guess the origin, and it's pretty satisfying to pull it up on google to see your high because you looked at spelling. This novelty has come at the expense of many other things that would have increased its utility.

I guess I'll add one thing to list benefits, this probably has resulted in different dialects of English writing things the same way despite saying them differently. Singaporean English is very different from Scottish English, but the written form of the same statements for the most part decipherable by the other dialect.