But how is that not power creep? You don't get a Feat for free normally in D&D 5E. I mean, maybe you should, and a lot of campaigns run that way, but you don't, and that's quite significant. On top of that, several of the Supernatural Gifts and a slightly smaller proportion of the Dark Gifts are arguably superior to the vast majority of Feats in terms of raw power (even accounting for downsides with the Dark Gifts). The real odd one out with Dark Gifts is Second Skin, which AFAICT, is nearly 100% worthless*, where all the others are at least niche useful. I do like them, and it's cute that a couple let people who want 1 to be a "critical fail" can "buy in" to it being such.
* = It gives you Alter Self 1/day, but only into a single specific and distinctive form. It does not give you any natural weapons or anything, even though it describes some of the example forms like they'd have them, and you're not allowed to do that thing where you switch the benefits, nor change the form. I feel like I'm missing something big but Alter Self pretty explicitly doesn't give you any benefits beyond looking different unless you choose the amphibious or natural weapons options, which you are forbidden from doing in this case.