IMO one of the greatest parts of a pure linux phone is that nothing is new. It runs the same apps as my desktop and works in the same way, so I don’t have to learn two sets of apps. Other than stuff like call management and Phosh, the desktop environment I use that’s tailored for small screens, I run all pre-existing software like systemd, wayland, firefox, nautilus, etc. IMO the biggest hurdle is hardware support, since only a few phones are able to run pure linux, and even on those few, there are still many parts of the hardware that are not supported.