I honestly don’t really get what there is to gain by using “Desktop Linux”.
More freedom I guess. I remember my n900 and how fun it was to just ssh into it and dig in my home directory, install apps with packet manger, edit config files with vi and so on. It really felt like having small Linux machine in my pocket. With Android everything is definitely more locked up but then again, I'm not sure what would I do if it was more open. Writing apps for Android is easier than for desktop (or just as easy), there are no more hardware keyboard phones so using terminal on them is terrible anyway and phones just work anyway so there's no need to mess with the configuration. Personally I mostly gave up on the 'Linux phone' idea and if I need any new features I will simply write cross platform app that runs on Android (for example with tauri).
It's a cultural thing. In Poland because of the climate, central heating and probably some other habits everyone has a carpet so you take your shoes off because carpets are hard to clean. In Spain because of the climate you don't have carpets because stone floors help cool the apartment down. Bare stone floors are easy to clean and are cold during winter so you keep your shoes on.