I have some of the same questions. I want to use one of these services to put student loan and rent payments toward min spends for CC sign up bonuses. I'm trying avoid BB/RC/Serve because I do a lot of remote field work and can't always get to stores to buy/reload gift cards. It looks like William Paid is dead. I created a Plastiq account but I don't find many US payee's listed (I tried Wells Fargo for student loans and the only listing was Canadian).
Can Plastiq send a payment to anyone or only payees that have signed up with them?
Is there a better service for US based customers?