Recently, incidentally i've seen this Dutch Queen Cover band "Miracle". At first i thought, well nice but there is no passion in their interpretations/covers. I think this whole cover- band idea regardless which band your covering is pointless and as a musician you should either try to get your own music across(maybe blend them(live) with some good covers of various artists), or become a top 40(wedding)band.
Even if your good at playing covers, i don't think it's very satisfying as an semi or pro-musician. Maybe the little money made from covering other musicians work make them do it, but then your not really passionate about(your own)music, i think.
i think coverbands are perfect if, like me, you were too young to see the original band in action. which leads me to.... check out the cover band i'm in link
you may recognise the name... the band was founded in '87 but has just has a line up change.
The best one I've seen is Gary Mullen and the One night of Queen show. Check them out.
As for your comment, every band started off as a cover band - even the Beatles.