Well, I love 550 as much as anyone but I will stir the pot here and post some sacrilege.

1) "550 can be opened up to yield a bazillion feet of cordage" - yeah, but if I need a 3 foot piece of thin cord, do I really want to open up & destroy a full piece of 550 to get it? Sometimes I think we'd be better off with a larger stash of something like Kelty TripTease plus a wad of mason's line.

2) "550 is considered useful by military survival doctrine" - yeah, that's because it's what a downed pilot has oodles of laying around after parachuting down. If it was 330 cord or 128.482 cord instead, that's what they'd be using for their shelters and fish nets, and that's what the masses would find in the surplus stores and in Uncle Hank's army box in the attic.

There are always outliers, but IMO about 94.55% of the time 550 is overkill. It is heavy and bulky for most of the jobs we use it for. When you have to carry your gear on your back and fit it in a limited space I think there are better options.

Excuse me while I put on my fire resistant internet suit...