At least personally, I want a phone that works similarly to my Linux machines. I have scripts that maintain a synchronized configuration across all of them, and I don't want my phone to be some snowflake that must be treated specially.

I want access to the same applications; I want to be able to run strace on random processes to understand what they're doing; I want to be able to organize my files under $HOME the same way I do in my other machines.

I want a Linux phone (ideally of a similar distro). It being open source is just part of that.

This is also the reason why I'm not really attracted to PineTime, despite it being open source.

If by polish you refer to aesthetic stuff like animations and whatnot, I don't really care about it.