> This applies to PCs and much more so to phones - on phones standard of "trusted" is rather lower, and increasing the number apps has real downsides (battery, performance, etc)

I'd argue this applies more to PCs and less to phones, since the security model for most desktop OSs gives all applications access to all user data, so you need to completely trust everything you install. On Android (and I believe ios) all applications are sandboxed. You can also prevent them from running in the background to limit impact on battery/performance.

Although I still agree that I still don't like installing junk on either, and phones still aren't completely immune.