I think one issue I have with SOS chaining is that it just felt too mindless for me... and not in a good way. It still required a bit of concentration, but for me, I found it too easy to lose focus when doing them.
I think that's the reason I like them. All shiny hunting methods are pretty boring, so the more I can just watch a movie or play another game while doing it, the better.
I also don't mind the enemy going 2v1 on you. I think it opened the window for good challenging totem fights and in the wild, it's easy to ignore since it doesn't happen that often (unless you adrenaline orb, which means you want it to happen all the time), you can run away from it too, so it really is a non-issue outside of the totems and made usum one of the hardest pokémon games (and very fun to play because of it).