I actually think amulet looks like (possibly) one of the strongest cards in the game- or at the very least a major trasher. It is like a steward mixed with a JoaT. Let me explain the benefits;
-In big money it can trash estates quickly and gain a ton of silvers. Sure, it can miss the shuffle, but then you could just get an extra one. If you have already trashed your estates, you can gain a ton of silvers, or trash coppers.
-In engines it is also very good. It trashes two cards with every play, and doesn't gum up your deck as much after it is done trashing (if you play it), so i'd prefer it over steward in most cases, especially if you are fighting over villages. Also, the duration effect gives you a better selection of cards to trash; if you play steward, you might do something like trash copper/estate where with amulet you could trash double estate, amulet is less likely to be unable to trash due to not having enough trashable cards in your hand, and amulet doesn't instantly destroy your chances of buying anything on the turn that you play it.