I do it sometimes when modeling cars... it's not "Cheap" or "unprofessional". I personally prefer other methods, but it's about the final result, not how you got there.
www.stevenegan-cgi.com
"Your weapons are no match for ours! People of Mars, surrender!"
"Um, this isn't Mars. This is Earth."
"Earth? Earth-with-nuclear-weapons Earth?"
"Yes."
[long pause] "Friend!!"