Hear me out...😁!
If Bass makes the XP, we go up by 4. Detroit now has to score a TD rather than a FG, so they're likely much more aggressive on their last drive. Do they score? Not sure, but the way the D was playing at that point, it sure seemed like it was coming. If Detroit scores the TD—if there is any time left at that point—then the Bills need a FG just to tie, and then it goes into OT to who knows what...
By missing the XP, Detroit plays it a little more safe and (for some reason) is satisfied with playing for the FG and OT, leaving us with juuuuuust enough time to break the tie.
Not saying Bass did that on purpose, of course, but the end result...?
😜