What would a Saints playoff berth mean

Consider this

The Saints missed out on Jordan Jefferson, Kenneth Murray, and Jalen Raegor( Picks 22,23,24)the year they took Cesar Ruiz. The year they terribly needed WR and LB help, and they had to settle for OL based on what was still available in their cloud.

So despite your assessment, a few slots can make a big difference in availability of players that fit your team at positions of potential higher need.
I'm sure it's easy to think of countless specific examples. It's just as easy to think of so many examples of players drafted earlier when there were players taken later that ended up being better. I mean, statistically, over decades of drafts, does overall performance difference end up being so much different within such a small range? I'm guessing yes, but hardly.