I think the recommended set w/Cornucopia, Guide is the Bane card.
This is not a good Bane card.
It's a funny one. Obv. it's a way better Bane than an awful card is. And it makes you think about Guiding just to get the Guide back.
I agree with LF that there's probably a good reason to Guide a lot early on. If your best card isn't in your hand, man, why not get to it. In Page/Peasant games, you Guide away good hands constantly, to try to upgrade faster. And of course sometimes it's a nice defense.
Even a single Guide is fine. Sometimes you don't have a specific reason for Guide, it's just some nice insurance. Sometimes it's just the best thing you can get for $3, and you build a rockin' engine that doesn't need them, and late in the game there are three sitting in the Tavern, waiting for a dud starting hand that may never come.