Sadly, this does make a difference. Whether we want to admit it or not, there are a lot of impressionable people in this country and a healthy percentage of them vote. To the extent that these concerts (and other entertainment-centered and programs)bolster Obama's cache with the general public, they really aren't anything short of in-kind contributions to Obama and the DNC.
It's depressing.
I wouldn’t get too depressed over this. These are court appearances only - the great unwashed are not invited to attend, so although they are promoted to great media fanfare, they are in reality a beltway only venue. I lived in DC for a number of years and saw firsthand what the playing rules are.