still relatively BCS was new in 2000. BYU was not going to BCS once it lost to Hawaii and probably would have been excluded anyway.
Back in 1996 there was no BCS. But it's predecessor, the CFBA did and again, the CFBA only had contracts with four bowls that grew into the BCS in 1998. Having said that, the CFBA was not considered that big a deal and when BYU played in the Cotton Bowl, it was still considered one of the four most important NYD bowl games of all. It still probably ranks as the fifth most important bowl game. Not plaing in the CFBA game really was no big deal. BYU had never played on NYD prior to the 97 Cotton Bowl and so that was a huge game regardless of anything else.