Use case scenario:
Was chilling last night with my full catalogue and shuffle, eyes closed, monitor off. Heard a few tracks I wanted to remember about before nodding off but had to turn my monitor on to add to playlist. Would be great to have a shortcut to add the track to the last added to playlist.
I have my magic trackpad 2 setup so I can control roon without looking or using a physical keyboard. The add to playlist shortcut is the missing key! So far on the trackpad I have it set so that the bottom left corner click goes back a track, bottom right corner goes forward a track. Three finger click pauses/plays. Four finger click opens search and brings up virtual keyboard. Top left click goes back (like clicking the back arrow), top right corner click goes forward.
Anyway, just an idea.