I saw it about a month after I started playing bass, and stuck with it since . I self taught but after watching videos on it more recently people seem to go for the index - middle - ring order of picking? Does everyone here do that?
I always always always without fail do the opposite, and find it much easier.
As for why I do it, I dunno, it feels more natural. It's so ingrained into how I play I will automatically just start with my ring finger now. Anyhoo, players who use it - Troy Sanders from Mastodon definitely throws a third in for faster passages. I also believe the Unearth bassist uses three, as does the Black Dahlia Murder bassist. Alex Webster (legend!) of Cannibal Corpse fame does as well I think. Also Dream Theater's John Myung too.