Their first fight was awesome and super competitive, Cody almost finished TJ in the first. Plus it was aired on a massive card, so maybe their thinking that some casuals will be interested in seeing more of these guys.
But I agree with you on the general premise that instant rematches are bs. They seem to make them when they don't like the outcome of a fight, which is pretty insulting to the winner. But, the outcome ends up the same 9 times out of 10 and I can't even think of an example for that 10th time, so it's really a waste.