In another slight thread drift away from performers watching their own fingers, can I say that watching a musician's fingers can be enthralling, if you happen to play the same instrument as them, though nowhere near as brilliantly. I play guitar a bit, and do sometimes find myself looking as much to what the performer is doing, as listening.
I was at a superb concert last night, with Jenna Reid (fiddle) and Harris Playfair (piano). Would have dearly loved to see more of what Harris was doing, (again being a piano player myself), but the grand piano was well over to one side of the stage, and I couldn't see the keys. Whereas I guess the many fiddlers in the audience were focussed on Jenna's immaculate playing, and trying to work out what she was doing.