Steve,
In the beginning of the competitions, the whole concept was to test the maker as well as the knife. Thus the maker had to use his own knife and be able to perform. These competitions are watched closely by lots of potential customers/buyers and they would naturally be more apt to buy from someone who is not afraid to put his knife to the test.
One thing that may not be clear to some of you guys is that any deformity or damage to the knife after the competition starts is grounds for disqualification. The officials run their fingernail slowly down the edge, feeling for chips or rolls.
The blade will, of course dull slightly with the abuse, but it should not be damaged. No sharpening or stropping is allowed once the competition has begun. The thing usually starts with a 2 X 4 chop against the clock, which tests the knives overall integrity (see if dont fall apart) as well as the edges ability to take the abuse. From there it goes on to other things.
The competitions allowed makers to show their stuff and what their knives could take and not be damaged. Some of the later competitions allow contestants to use knives made by others.
Lin