It's the rule I live by when it comes to working on cars.
Sure, I could be happy sticking a KB on my 07 and sitting around 450, but I could do heads, blower cams, and LTs and make 500 or more.
Then why not upgrade to a bigger blower instead of buying the smaller one? Hmm..that would put me over the 500 safe limit on these motors so I'd have to forge the internals or snag an MMR750 shortblock. That opens up another 250 horse maximum!
It just compounds upon itself.