Most MMOs have a steam launcher, they tend to work better than the native launcher from my experience with them
I don’t believe WoW is on Steam. It’s likely that Steam was just open in the background and popped up over WoW.
Ahh, I didn’t bother to check, I just know that I have MWO, STO, SWTOR, and could play EvE through steam. I figured blizzard would eventually jump on the bandwagon.