This is one of the later Vitaphone shorts--known as a "Melody Master". These later musical shorts generally were more straight forward and had simpler sets and no real story to tie it all together--just a famous band of the day doing their stuff.
Like the other reviewer, I'd never heard of Skinnay Ennis before I saw this short. I did a quick read on him on IMDb and found that his death was a bit sad and premature. As for his singing, Ennis was very, very smooth but not especially strong. It's pleasant but not at all distinguished. Because of this, I preferred when the jitterbug style song followed. And, unlike all the other jitterbuggers I've seen in "Melody Master" films, this team was actually pretty athletic and talented (the rest tended to be very tame--probably to appeal to a wider audience). However, the team STILL is downright zombie-like compared to the frenetic jitterbugging you'd have seen in Harlem at the time (I've seen film of them dancing so quickly I almost felt like it was faked). The rest of the songs are ordinary--though it did heat up a bit near the end.