Not sure what do you mean by that; if you compile mpv with lua support (in case your distro/whatever doesn't ship it that way, that is) you get a clicky-clicky little osd thing within the mpv window that suffices (back, forward, playback control, volume...)
I have used that UI in MPV, but it just wasn't satisfying.
VLC is a native GUI application and I just find the interface more easily usable.
Not just play/stop, etc, but all of the preferences, etc are via a GUI interface.
Totally personal preference, I just prefer VLC over MPV.
Somewhat counter to all of that, I do often use the hotkeys to control various features during playback (audio delay, that sort of thing).
I just feel that VLC is a more GUI oriented application, and in spite of being a mostly command line linux user, I do enjoy a floating window manager desktop (fluxbox is my long time preference).
Thanks again for the reply!