I don't actually like Material Design very much, but it isn't as if I like Apple's iOS 7+ "flat" design either (though it has at least gotten better over the years). I think having consistent mechanics is not only useful but "very important", but I also never felt like Google's apps on iOS were particularly "alien": they seem to be using the built-in scroll views (I have a somewhat low tolerance for this, but I honestly am not "super picky" about subtle things that could be different... I have friends who are designers who turn up their noses at a control of weird corner cases that feel like bugs aren't clearly exactly the Apple control, which I think is ridiculously snobby) and their overall layout feels like any other mobile app.

I do hate hate hate the Google Docs app, but it isn't because of Material Design: it is because the concept of how the app thinks of editing mode vs. viewing mode is extremely confusing, and I always manage to end up dismissing the very button I need to access the editing mode in my quest to enter the editing mode. (I also often end up adding a comment by accident and my attempts to cancel the comment pass through some workflow where I cancel the cancellation of my comment... I feel like this entire concept of double-cancel is insane.) But they would almost certainly make that app just as difficult to use with any widget set.

But the actual design of say, the YouTube app? It is fine. To be clear: I hate it when an app sucks... I am ultra-picky about fine details in products involving the spacing and alignment of widgets, and I find that almost all "bespoke UI" truly pisses me off, as most designers frankly tend to suck at coming up with good components that make sense in context (and then the engineer that builds them tends to fail to push back on them sufficient and you get a cluttered and disorganized mess). But it isn't because I am being snobby about "it has to be an Apple control or I won't accept it": it is because I know a lot of typography (which itself is probably more than a normal user, who wouldn't even care about spacing and alignment!). And seriously: that isn't the YouTube app, nor is it the Google Maps app.

And then, at the end of the day, you have to ask whether the vast majority of people with an iPhone are even using Apple's own apps very often. I appreciate some people do; the person reading my comment in anger right now is likely thinking "I DOO!!". But seriously, now: how much time do you think a normal user is using their phone to use Facebook or TikTok or Twitter (which I bet you don't use at all and claim these are horrible apps for horrible people who don't know better, yadda yadda) vs. literally the entire rest of their lives, mess less using the Apple apps?

I use Safari (though I wouldn't if I felt I had actual choice... "thanks, Apple" :/), but it doesn't use the standard iOS app bar controls either ;P. Other than that, I still use Messages a lot (though most of my friends gave up on iMessage long ago, and switched to WhatsApp or Facebook Messenger), Notes every few days, and the Phone app once a week or so; I go into the Settings app a lot, I guess, which feels weird, but it is what it is ;P. I used to use Camera a lot, but in addition to also being fully bespoke UI, I don't go outside anymore as all the events I go to are cancelled or virtual :( so I have nothing to take a picture of anymore) I am actually going outside today, but probably not many: I don't actually consider fleet week to sound like an exciting photo op).

I use Calendar, which uses normal iOS UI for the editing of stuff but then uses seemingly entirely bespoke UI--that I don't think is very good, BTW--for everything else. And hell: I think "normal" users don't use even the Calendar app, as 1) the only reason I am using shared calendars is because I have a fancy white-collared job, where other people insist on using calendars constantly with meetings they want to remotely manage, and 2) I am one of those rare weirdos (that are over-represented on Hacker News) that prefers to keep all my data locally and so I liked how the Calendar app was only on my phone... most everyone else I know uses Google Calendar, and I bet most non-tech people just go into the App Store to get the Google Calendar app to access it (I know the other fancy white-collared people I work with do this, because they are always confused at how my Apple Calendar renders stuff when I ask them questions, but I still believe fancy white-collared people are weird so this isn't a great data point).

But so then, for real: despite being "old" (almost 40) and "out of touch" (I don't ever post because I feel a bit weird doing so) even I use Facebook and TikTok and Twitter (oh and Instagram!) more than all of those Apple apps combined... and none of them seem to think Apple's stupid iOS 7+ navigation bars make any sense and so they all have something more similar to Material Design's app bar. I think this is a good thing; and, even if I didn't, I will claim I would have been unlikely to think about it much as these are the apps I--and I continue to bet most normal people, even way way more so than I--use most.