Lucky charm isn't worth investing in because you can have 5/5 just with items and the romantic trait. Just craft a staff, a rabbit necklace and a rabbit belt, and loot/buy some lucky charm boots.
Equip them when you start looting barrels and stuff, and equip back others items if you feel necessary to have better stats than lucky charm for a given fight.
If I recall, it's even possible to use a crafted dagger (require dex 5) that you must have created at low level, and a shield around level 8 which gives 2 lucky charm so you can ditch the rabbit stuff on a mage, but it's not that easy to do because the shield requires some strength, and I don't think it's a good idea to put weak weapons on a physical character. Lategame you find good INT items that gives also strength sometimes (necklace often, ring sometimes I think?), so you can do it, but I didn't do it myself (I hadn't crafted a low level dagger, so I had no lucky charm dagger my mage could equip, but I had the shield).
Lucky charm procs quite often, and might be a source of a lot of (unnecessary?) money.
I didn't really need any loot I got from lucky charm, so the main point is money, and the good feeling you have when you read "lucky find".
Note that it can give you a lot of money early game, because when it procs within the Homestead, you get lvl 20 items.
