It seems absurd to let Google Photos slurp up your data server side when your iPhone can do 80+% of the photo categorization automatically. It’s equally absurd that Apple has a glacial pace of change for the user side.
Photos... just sits there. To get a new photo to my desktop it's faster to open Google Photos on my desktop and download the photo from there than wait for both Photos.apps to finish syncing.
The uniformity of UX is worth the glacial rate, IMO. The more ScrollViews with arbitrarily laid out content (Photos seems to have these increasingly), the less intuitive I find apps. In Photos, I find it hard to get a sense for what menu-depth I'm at. Apple has a very logical master-detail layout across most apps, and I hope with Mac Catalyst that Apple continues to enforce consistent UI practices.
The more freedom developers are given to put any old layout, the more apps start feeling the way Windows Forms, WPF, and UWP feels on Windows; it's like you have to start thinking about "Okay, when was this app designed?" to figure out how to use it.
I think most people are probably fine with the tradeoff between convenience and features that centralization offers, so unfortunately people that aren't are stuck with more niche products (or Apple, I suppose, although I don't think i-cloud is end to end encrypted?). I say they're stuck with niche products because I don't think it makes sense to try and offer a slider between convenience and privacy in one product, since the interface and feature sets would be so different.