I am aware of the why, it's claimed to be e2e. But then it shouldn't be touted as a "pro" when compared to Google Photos which the site's home page is asking me to do. Hence the question.

As for iOS, Apple controls the whole stack. Whatever ML they do, they do it only on devices capable of that level of ML.

I can buy the cheapest android I can find with a 10 year old mediatek processor and search for pictures of my dog and it'll show it. There is a value to doing the heavy things on a heavy hitting server.