Here is my idea of using cursed weapons or items.
Make the item great. Make the Player have to make a choice of using it.
Imagine a party of Heroes have +1 items. Then they discover in an old crypt a +2 item. Everyone wants it! But this one comes with a curse.
- The weapon hates the users, and natural 1s cause a nick doing 1D6 damage.
- The cloak is nosy, and all stealth checks made in its presence is at a disadvantage.
- The ring causes the Hero to have minor Tourette, and all diplomacy rolls are at a disadvantage.
- The helm causes all food to lose taste and potions have no effect on the Hero. Yet, poisons still affect them.
- A suit of armor offers no protection against followers of an enemy god.
Whatever you want really. You just pick something kind of bad to attach to the weapon and see if the players now want to use it. Most of the time someone will. But now there is a cost.
Here is the other thing. Most GM has cursed items are seen as something you need to have removed. Go find some NPC and have them cast Remove Curse spell on you.
With these types of cursed items, the players just need to disown them. This means that as long as the Hero claims ownership, they receive the curse.
The game is best when players have choices. Not just between two roads, but on everything.
This includes items. And choices are best when they are not easy.
An obvious choice is, do you want a +2 sword? If you have a +1 sword that is simple. But if you have a +2 sword that doesn’t allow you to ever use a potion, now you have to make a choice.
Next time, they find a +3 Armor but is causes them to do (-2) damage. Not as clear-cut. A ring that allows them to become invisible, but they do not heal naturally! And so on.
In my time as a GM, I have had more than one cursed weapon sold or thrown away. Because after a while, the player realizes the item has too much of a cost.