As a cover band, and this may be obvious, you are an employee. An employee to the bar manager/owner and also, frankly, to the patrons. Thats really the bottom line. As a working cover band, there is an equation...
People + Dancing + Drinking = Sales; Sales = Good
Sales and commerce is what the club owner or manager wants; Typically the club manager wants to do a good job and thus, if they hire talent, they hire talent that they feel will do a good job at the task and will make their bottom line look as good as possible. They do not care if you think you are the next american idol or Paganini. If your band has a following and brings people to the club, keeps them there and those people spend money at the bar, you will be a regular band at the venue. The band does not have to be a great band...just fun, entertaining and engaging. A sense of humor is also very helpful. A good songlist that is aimed at making the patrons have a good time is important....not Dream Theater or other stuff that shows how great the band *might* be.
If you are band that takes itself too seriously and is there to show how great you are, then perhaps you should be doing originals instead.
The cover band circuit is a business...I have fun doing it, but it is a business. Commerce.