When has Eat to the Beat ever even tried to get a line-up to match the caliber of what Mardi Gras gets, though?
The bands are just there to bring back the AP F&W addicts and hopefully draw a few supplemental guests who may have chosen a different park otherwise.
Basically, the bands at F&W are just atmosphere while you eat and drink whereas at Mardi Gras, the artists are the main attraction. Although with moving the event to being daily a few years ago and adding a lot more food tents last year, this event could easily survive on it's own now as Universal's version of F&W if they really wanted.