It would've been a cool world if we got Linux that could work seamlessly between desktop and mobile. Imagine if you had architecture where apps were built as services with an API, and then you could connect either desktop or mobile UI to them. Heck, at that point you could even make custom UIs across apps, or pipe them together the way you do with shell scripts. And then you could also have a device like a phone which has all your apps and data, and you could plug it into a dock with more memory, GPU, etc. So, you wouldn't have to juggle a bunch of devices and sync data between them.

For most use cases though, you don't really have much of a benefit of running Linux over Android on a phone though. There's enough Linux compatibility on Android already to make it work seamlessly with your Linux devices. In my opinion, as long as the stack is open source and well supported, it doesn't really matter whether it's Android or Linux based.