Same thing in Canada. I was a kid when we moved there in '79. Most gas stations were half full serve, half self-serve, with the full-serve being like 3-5 cents more per liter (started at 19 cents per liter IIRC, but quickly went up). I doubt there are any full-serve stations left in Canada. Again, probably a holdover from an earlier time.
Not sure when auto-cutoff pumps were introduced, but IIRC, way back, you could easily overfill a tank and spill gas everywhere, and presumably the full-serve attendants were trained how to judge that better, AND were wearing overalls so that they didn't mind a small spill.
Imagine going in your Sunday best and spilling even 50-100 ml of gasoline all over them?