I dunno, perhaps they thought if Mahomes saw the back end close in he might fire one over their heads and bye-bye goes the cheetah, again. more egregious to me was not forcing KC into taking the kickoff from the 5 or from a squib kick, they get it at the 25 with not one second burned off. I hope the Bengals kick the snot out of KC next week, no one is giving them a chance and that's a mistake IMO.
I think too much is being made of not squib kicking. Assuming the Chiefs special teams unit is well coached, they would've been directed to immediately down the ball. Maybe a second runs off, maybe the field position is 10 yards better for KC.
Kicking it away to the 5 has some small risks too; you're forcing your coverage to play well and not give up an unlikely TD return.
What ifs aside, giving up 44 yards in two plays in 11 seconds was terrible. With 8 seconds left, the reason the Chiefs are trying to quickly hit for 15 yards is because the odds are better than that of a Hail Mary (or trick lateral play). And even if they don't get enough yards on that play, they still have a couple ticks for a Hail Mary. They have two pathways to victory (one via overtime) instead of a single 10% gamble.
I'm no defensive wizard, but I'm not paid millions to be one. In hindsight, it's easy to see the defense was all wrong. They rushed 4 linemen when you'd usually rush just two or three. Flood the field with extra DBs, and have a couple safeties downfield to help on intermediate or deep routes. Instead, they put 3 DBs so far downfield that the Bills basically had only 8 defenders on the play, and 4 were futilely rushing the QB.