Personally, as a keyboard player/lead vocalist in a cover band, I have always produced my parts using both hands, my feet, and my voice. I have never used looping effects or backing tracks.
I have however, watched performances with backing tracks, and when doing so, my focus is generally on the performer, and not the background music. A stellar performer in my view will stand out, regardless whether he is backed by tracked music, or live performers.
There are a few perks I can see from using backing tracks:
1. They never show up late, forget their capo, or have to borrow cables from you.
2. You do not have to call them to find out if they are available when somebody tries to book a gig with you.
3. They are always in tune, vocally and instrumentally, and their timing is impeccable.
4. They never have to practice, and they are still awesome
5. You do not have to split the money with them, they work for practically nothing
6. No power struggles or interpersonal problems with these guys, they are very easygoing, and will go with the flow
Wow, I am starting to convince myself to reconsider my circumstances!
Just kidding, of course, I love my bandmates, they are all true professionals, as well as good friends.