I always see articles like this and wonder what the big deal is... I frequently use PayPal Credit, store credit cards, and Affirm on larger purchases because I

I always see articles like this and wonder what the big deal is... I frequently use PayPal Credit, store credit cards, and Affirm on larger purchases because I like being that much more liquid. Then I realize that I always use the 0% APR option and that I've paid exactly $0 of interest to all of these services. I couldn't imagine paying 12% APR for the privilege of owning a $1400 synthesizer much less for a delivery order of sandwiches at a house party (as mentioned elsewhere in this thread). Side question: how are these services able to offer lower APRs than credit cards without collateral? Do they evaluate your creditworthiness on the basis of paying equal installments as opposed to revolving credit with a minimum payment? If so then how are they different from an old-fashioned personal loan from a bank?