Not knocking this, but there's a lot that goes into it.
How many fourth-quarter game-winning situations did all the quarterbacks face? Dak has the most, but did he also have the most opportunities?
Second, how high is other QBs' rating in the fourth quarter? Because not all QBs get the same amount of GW opportunities, QB rating in the quarter can be a measure for how well they play when the game's on the line, even if they are ahead.
Don't get me wrong, I'd much rather our QB have the most than the least and be playing well when those opportunities present themselves, but it's hard to judge the value of the information without context.