I believe there are 13 conferences in FCS but my understanding is the Ivy league does not participate in the playoffs.

That leaves only 12 conferences and 10 of them get auto bids. And 14 additional at-large...

Most conference champs in any given year will get into the playoff weher as a guarantee or an at-large.

Compare that to CFP there are 10 conferences and only 5 are guaranteed to get in. And almost with certainty a 6th would not get in just about every year.

So FCS doubles the auto bids (5/10) and the at-large bids (7/14) and has a much clearer uncorrupt/biased path to participation.