That could be true, although most of the MDF I've seen in the box stores (either 1" or 3/4" x 4' x 8') seem to have an extremely smooth surface on them. It would need to be sealed with a fast drying primer of some kind to seal it first though, because MDF is like a really hard sponge, it soaks up a lot of paint unless it's sealed properly.

Half of communication is listening. You can't listen with your mouth.