I don't think anybody does since there now exists a lodestone almost right next to the dungeon of a large selection of great monsters.
I think these guys who sail from Karamja to Ardougne and Port Sarim would be out of business if it wasn't for the fact they are NPCs.
I know for a fact I don't use these ships anymore. If I wanna travel between Karamja Island and Ardougne, I use the lodestones, simple as that. And that's what I do.
Of course when fighting greater demon, red dragons, steel dragons, etc. I use the teleport spell if I'm low on health or have full inventory as it's impossible to use lodestones during combat.
But other than that I use the lodestones. So yeah.