<font color='#000000'>Sure, if by "properly dressed" you mean "...with actual screen fabric or Goo" (yes, there actually is something called Goo that is specifically designed for this - it's made up here in either Belleville or Kingston, Ontario, Canada.).
Anyway, there are a few reviews out there comparing the "white wall" approach to a proper screen, all of which conclude that, while anyone can watch a picture on a wall, the screen does serve as a far better surface in terms of all of those important aspects like black levels, contrast, etc.
I know that many big-name screen manufacturers sell their fabric for a fraction of the cost of a full screen setup. Then you can mount it as you like...Likely the way I will be going once I win the lottery
and can afford the setup I want.
Evan Powell and the team at ProjectorCentral.com seem to be quite an authority on this stuff....thorough and objective articles...</font>