Dude, it's capitalism to its fullest extent.
No bowl exists to make students feel better about themselves for a job well done (and no bowl ever has existed for that reason). The bottom line is that the stake-holders (tv and the bowls themselves as "non-profits" and to a lesser extent probably the communities where they exist) all make more money (they think) if they can have access to even a 4-5 P5 team. Not to mention the pure math of it all - there was a real chance that there would be way too few teams with winning records to fill all the bowl slots (probably a little less risk now that more leagues are playing, but could still happen).
To the extent that this is about "rewarding" anyone it's about rewarding brands for having a large following.