But I don't get why they're so expensive?
Because the sailboat market is small and they don't make enough for the economies of scale to lower the price and because it's for a boat.
are they $1750 more convenient than Winchers?
I think so. IMO, the difference between a Wincher and an ST winch is the difference between a Yugo and a BMW. They both get the job done, but one does it with a lot less drama.