If you go first and open Sea Hag, and then I open Sarcophagus, and we each curse once per shuffle, I'm going lose the Curse split 4-6. You could argue, of course, that the Sea Hag practically becomes a curse when spent, so it's comparable to a 5-6 split. Each shuffle I encounter two curses more than you, but in exchange my curse giver is a silver, which allows more flexibility and growth. In comparison to other curse givers, it would generally be unwise to purchase many Sarcophagi since you'll take on too many curses.
Rather than raising the price to $5, one could lower its value to $1 so that it is a cursing copper rather than a cursing silver.