hmm..as long as it's composited well, looks fairly realistic and believable..it floats my boat..;) from my hours of experience with backgrounds (that's what, about 30 minutes?..;) I think it's just easier to create a quickie background..
some folks do this for serious artistic reasons, some of us do it for fun..there's always things to learn, and one thing you have to remember is how many beginners start here..just part of the price we pay..;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)