Stripe's terms of use prohibit both weapons and virtual currencies. If Simplify's terms of service prohibit either, I can't find the relevant paragraph. That alone makes Simplify somewhat more attractive.
Source: https://www.simplify.com/commerce/docs/misc/legal/merchant-t...
Much, much less restrictive than Stripe, and cheaper to boot. Now adult websites can switch to this instead of CCBill (which I find more sketchy.)