When done correctly, the underwriting is actually significantly better as it's done on a per-transaction basis, incorporating the item itself (ring purchases are significantly more risky to finance than sneaker purchases). You can also incrementally dole out a credit limit, rather than giving someone a $10k threshold upfront without any veto power over how they use that amount.

That being said, there are a ton of hucksters in the industry and I suspect we'll see most of them wash out in the next few years :)