Together with the 'Command + Shift + ?' help menu, you don't need a mouse.
There's a lot of good info here: https://github.com/orta/keyboard_shortcuts/blob/master/READM...
For me, the most obvious/immediate "bang for the buck" is enabling bluetooth when I sit at my desk. If I don't, and use my Macbook from the living room, the distance is just awkward enough, on bad RF interference days, to continuously get the "Connection lost" and "Reconnected" message for the mouse.
This is fine for MacOS but it relies on accessibility annotations that most apps I use were missing the last time I used it.