>>37866995IMO, SuMo [Soo-Moh], USUM [Oo-Sum], and SwSh [Swoosh/Swish] roll off the tongue easier than SM [Ess-Em], Ultra Sun/Moon, or SS [Ess-Ess]. I'll probably say the phonetically easier ones in person as long as the person I'm talking to understands me, and the shorter abbreviated ones online (SM, USUM, SS), again, as long as it's understood.
If i'm just talking about the individual game, I just say the name, Sun, Moon, Sword, Shield.
It really doesn't matter in the grand scheme of things. People will eventually just say what's easiest for everyone and that will catch on. Anyone who really gets this salty about "muh letters" needs to get a job and move out of their older brother's bigger bedroom.