I'm not really into that kind of thing, but I will never dis anyone for liking them. They fill a need for some people to hear the songs in a live setting.
I came from the age where there was a Broadway show called Beatlemania, which had considerable success and even was turned into a film. The feature released in 1981 was a major failure, proving that this type of performance is something for those wanting to go out and hear something very familiar. The Broadway show itself did spark some small music careers for various members of it's history, two I can remember with Tom Teely who played George Harrison and one for Marshall Crenshaw who was John Lennon.
To those who like a Wiki, here it is...
Beatlemania (musical) - Wikipedia, the free encyclopedia
At best, it can be a start for musicians today of they decided to go more original. That can be a rare thing, but as proven it happens from time to time.