I didn't mean to in any way imply that people can't improve their game play skills while being more concerned with other aspects on the game. Repeating the term "skill building" in the responses consumed too much space.
I personally enjoy playing the charts and getting better at playing the charts. 99.9% of the time I spend playing this game is solo quickplay and I've never played with more than one other person (my housemate/landlord, who introduced me to it) and I've never played online. Come to think of it, it's exactly the way that I play piano--I never play with or for anyone and actually prefer if no one's around to hear me. I play because I enjoy playing and listening to the music and because it's relaxing, and I play RB the same way and for much the same reasons.