I have no issue with UCF doing this under the current circumstances. I had already figured some polling organization would give them a national title and them claiming one makes sense. The team did everything they needed to do, they won every single game on their schedule, those players did everything they were asked. Same went for 2010 TCU, 2008 Utah, 2006 Boise State and 2004 Utah.
In practically every other sport, if you win every game, you win a championship. College football at the FCS, DII and DIII levels, college hockey, college basketball, nfl, nba, nhl, mlb. Obviously the latter have no real shot of winning every game they play, but the point stands that in any other sport if you pull off an undefeated season or playoff run, you likely raise a trophy.
I think UCF doing this does a few things. One, it gives those players something more than just a bowl win. Two, it sends a message to possibly expand the playoff. And three, it raises a question about the future of the Group of 5. Should they continue playing in the same division as the Power 5? Whether it was the BCS or CFP, undefeated schools from the "mid-majors" never got a shot at a title. Boise State, Utah, TCU, all of them won every single game, but won't be remembered as champions from those years. Maybe another division makes sense if the CFP continues the way it is.