Do artists/entertainers accumulate positive merit when people enjoy their craft?
According to the Talaputra Sutta, one time an actor approached the Buddha and asked him if he would go to heaven with the devas because he made people happy and forget their worries.
The Buddha tried to dodge answering, but at the actor's insistence, he had to tell him that he'd probably go to hell or the animal realms.

See also:


This question: Will actors really go to hell?
My answer to Are actions in computer games bad for karma?