Dumb question about painting an engine?

[jorgensensc]

Kinda a dumb question, but here it is:
I noticed alot of guys and engine builders put a block together with pan, timing cover,heads, and even the fuel pump then paint the whole thing one color. Does doing this help seal the motor and all the gasket interfaces? I only ask because I personall like it when the block is one color (maybe orange), the heads a different color (maybe black), timing cover, etc.
I am not putting anyones work down at all, I'm just curious as to the thought process or tecknique being used if any. Or is it just easier and that is why builders do it?
Thanks and I hope no one takes offense to this thread if your engine looks like this, because mine does too, but it drives me crazy.
Shawn