"I don't see competition as being that much different."
I disagree. I spar regularly, but even in full contact sparring there is a certain amount of controll. The focus is on learning rather than on a KO.
That little bit of extra agression and the fact that you often know nothing about your opponent makes it(competition) a very different experience to sparring in the dojo.
Plus the added tension of having loads of people watching and judjing you, really puts you in a state of adrenaline overload similar to what you would experience in a real street fight.This is perhaps 1 of the most important things to learn to deal with, to be effective, and comps are probably 1 of the best ways to get the necessarry experience.
Also in the dojo protective gear is usually worn to lessen injuries.
When the gear comes off for a comp the pain factor can cause you to fight somewhat differently.
I highly recommend competion for anyone who seriously wants to improve their fighting skills.
OH and 1 more point. Knowing you have to face someone in the ring next month makes you train really hard!