The way this combo works is say you have a sea hag game with bad to no trashing. You buy a sea hag on the first 2 turns and a second pretty soon after. Assuming your opponent buys one as well you know the curse pile will be depleted. Start buying duchies over golds when around 7 Provinces are left in the supply and buy estates over silver with 5 provinces left. You will deplete both piles relatively quickly and since your opponent's deck is so clogged with curses, it will take him a long time to buy provinces - so long, in fact, that you can probably deplete both estates and duchies with 2 or 3 provinces still left in the supply. While your opponent will have more provinces than you, you will more than make up the difference with duchies and estates. And the best part is that once your opponent realizes that your trying to end the game quickly, he cant respond by buying vp without helping you in your goal. You can also do it with alternative vp cards instead of either duchies or estates. (A similar type of strategy works with the other cursers but to a much lesser extent since they don't slow your opponent down nearly as much) For reference, in Geronimoo's simulator this strategy beats the regular sea hag bot around 60 percent of the time.
Works with: Hoard, alternative vp, +buy (which can help you buy 2 estates at once), other cursers, duchess
Doesn't work with: strong trashers, lighthouse, wharf (since it helps your opponent speed up the game), opponents who don't buy sea hag, engines