Half the "Stats" do nothing.

[cromignon]

The Melee Combat, Resistance, and Luck stats don't perform as described. Just to check, I've edited my save file to pump each of these up to 20, and found no change in the amount of melee damage dealt (or even the amount of damage a monster takes when it "touches me", as the stat description is worded), no reduction in the amount of time poison slows me or frost immobilizes me, and no real increase in frequency of bonus drops.

I haven't really looked into it, but I'm guessing most of the permanent pickups that claim bonus damage against certain enemy types don't do those things either.

All the stats that actually work do so very poorly. For example, the only way not to get killed in one shot by the Hell Baron's fire breath is to crank the Constitution stat up to 20 or more. In fact, 20 seems to be the magic number as far as seeing any real change in any of the three functional stats, save for Observation, which is basically just a score multiplier.

[Mori Yamamoto]

Oh, that kills you almost always, and the item they work you were just not looking at it in game.