You make good points. The SDI class isn't a normal recognised class by most standards, although is a good class and introduction. No class can fully prepare a diver for every single condition they might experience.
But, regardless of what everybody said here, there are still more industry accepted reasons to use the buddy system than not. And yes, this is just ONE example, but over the years I've performed 3 rescues where another diver had fishing line (twice) or Kelp (once) wrapped in a manor around them that they could neither reach nor swim free of. And even though gear R&R is a skill taught by training agencies, far and away the vast majority of divers of ALL levels are neither comfortable nor competent at it in the open water.
These 2 of these 3 people were fairly to extremely experienced divers with years of diving under their weightbelts. One was a stranger. But of the 2 I don't feel either would have had a happy, positive outcome of their predicament without my intervention. Over the years there have also been the cramped divers I've towed to shore. Sure, they can reach the surface and lay there, hoping somebody assists them before a boat hits them, but without a buddy it makes for a long and very miserable experience.
Then of course there is the experience and enjoyment of it. If you find that ALL the other divers in the world are a burden and just tend to get into your way, then quite possibly I'd say the issue lies with the constant to that equation.