I don’t see the attraction of using AfterPay etc for small purchases like some people do but I have use other BNPL services in the past for larger (furniture) purchases. Basically for exactly the reason you say, allows spreading the cost out without credit card interest. For me it was really just a way to avoid draining savings after having just bought a house and I was comfortable about making the repayments. 

 Yee exactly, can be very useful like that. 

I think part of the attractiveness is it is also supported almost everywhere. And it likely encourages more sales for businesses who offer it at checkout as people can do as it says "Buy Now, Pay Later" lol. Instant gratification.