I use my tablet with a keyboard (no mouse). The experience is so-so. For example, hot keys in Fennec work only in English layout, some keys work only when a particular widget is focused, etc. Some apps like SkyTube don’t support playback control keys (though one would expect this from a media app). Some apps (e.g. Termux) show useless on-screen controls, duplicating some hardware keys.
The bottom line: developers don’t test apps with hardware keyboards. Expect bugs and annoyances. But if you need to type text (even small amounts), hardware keyboard saves a lot of time.