Yes. I get that and agree with you. But how many times out of 10 did Allen "hit the spot?" And did he hit it more frequently than anyone else? Who knows? Trent, you, me, the rest of the world?
None of us know, since it's not a stat that's maintained. It's a concept that only could be obtained by watching every single throw and cross-referencing it with the play called, the players on the field, the weather, the position of the moon...
But completion percentage has a long and deep history and is highly correlated with NFL success. And it's been broken down eight ways to Sunday in ways that show Allen to be very low relative to good NFL QBs. That's as objective as we can get...