Personalized plates... why use them to reiterate the type of car they are on?

This tr4a guy is clever... so extra points for that... and I use it as an example of what I look for in a personalized plate. The rest of these are a waste of time and space, they had a chance for humor greatness, but failed to achieve

the rest of these, just leave me flat when I was hoping for witty, clever, or inovative