I do think it's a bit overblown, but at the same point you can go too far with it and end up hurting your flexibility by having a bunch of void years on the end of an older player's contract or the contract of a player you want to part ways with. And, if the unexpected happens like COVID, you end up losing players like Marcus Williams and Armstead.
So, it does put a premium on making sure you are giving contracts to the right older players. It also puts a premium on being good in the the draft, particularly the mid-to-late rounds of the draft to fill out your depth and roster with quality players that you can't really go get in free agency. Of course, the draft is the key for all teams, but I think the way the Saints do the cap makes it even more important.
Regarding flexibility there probably aren't a lot of players they do want to walk away from but it's clear that Cam is at the point where he needs to retire or take a big pay cut. If he refuses either of those you are stuck with a lot of dead weight and if he does retire you are stuck with some dead cap due to the void years on this contract. Then there is Carr. While I don't think DA had any intention of walking away from Carr, but the next head coach may want to cut or trade him. And to do that they would have to take some extreme measures that they may not want to do.