Yeah, it's not based on who's the best house from what guests see. This is an award of the cast giving it their all and from that perspective, I think from having to extend quite literally EVERY NIGHT, working the Microsoft night and working Tomorrow still (remember, HHN 28 still hasn't officially wrapped for them), they deserved it.
Saw was going to win last year from that same POV, but one of the actors in the cast decided to have a little too much fun on one of the last nights, so Scarecrow got it. Remember, Saw extended pretty much every night last year as well. It really comes down to a cocktail of GSAT, incidents, and willingness to work when Universal asks you to work + what gets passed on from Stage Managers to Show Direction as far as how the cast gets along or if there are any internal problems.
Also, they literally get nothing other than being able to call themselves House of the Year. There's no trophy or anything here. They give the cast a bunch of pizza from NYPD and that's it.