I put Cache out the other day, my girlfriend said it looked worthless. I was like, yeah.... it kind of is worthless.
I like cards positioned on a humble part of the power curve, but I struggle to find redeeming features to Cache. When I play it in a slog it often feels like a mistake, usually there is some other 5$ card that is motivating the slog, like a Garden's Market or a Duke's Duchy. Watchtower and Trader both make Cache useable, but they both do so in a way that's like, "ignore the inherent qualities of Cache because of this combo", it hardly makes the card feel well designed.
It's not to say I've never bought it, but I usually regret it.
When I try to think of things to try to do with it, the best idea I can come up with is Ambassadoring it in a Goons game where the treasure is like curses. But coming up with a way to make someone gain it as an attack doesn't make me feel like it's a well designed card.
What's good about Cache?