I have this Kess deck where I run the other cards and they are pretty amazing value because you can cast the discarded spells from gy and then the card again for even more value. They get really good with copy effects. I tutor primal amulet every chance I get.
Yeah, in a vacuum, it's not particularly good, and the CMC2 versions are much better. Once you bring in synergies though, this looks a lot more interesting. Copying it, making extra tokens or even just general artifact interactions make this a fair bit more attractive and should be at least worth considering.
I play it in my Daretti deck, alongside Faithless Looting and Tormenting Voice. It essentially costs the same as Tormenting, as you will net two mana after it's cast. But in Daretti, it gives you extra sac fodder, which the deck really loves.
I personally love the card and am glad I put it in.
Card advantage is not the same thing as card draw. Something for 2B cannot be strictly worse than something for BBB or 3BB. If you're taking out Swords to Plowshares for Plummet, you're a fool. Stop doing these things!