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.
"a. Illegal Activities
b. Certain Adult Oriented Products and Services
c. Illegal Drugs
d. Counterfeit Goods
e. Gambling Businesses
f. Money Making ("Get Rich") Businesses
g. Tobacco Products"