@SilentAssassin I wondered that too. The only reason I can think of is It makes it so you don't have to worry about timing missiles with your left hand, you just hold down your machine gun. The fact most people are right handed probably lead to this decision. Whatever the reason you get used to it. I've played the demo for hours and I actually forgot about the switch until I read your post.
I've played every Twisted Metal game and I just got the demo, does anybody know why this is the first TM that the machine gun and special weapons have reversed buttons (L2 & R2)??? Not used to it & you can't change those 2 buttons around.