Paypal is more demanding than most payment options about the prominence of their brand. They require, among other things, that you use their BIG, BRIGHT ORANGE

Paypal is more demanding than most payment options about the prominence of their brand. They require, among other things, that you use their BIG, BRIGHT ORANGE Paypal button and that if you offer other payment options, the grouping needs to be "Paypal -or - The Rest," and not an arrangement where they're suggested as inferior (or even equal). They also pretty much require that part of the payments process happen on their own site. All of that put together means that people serious about handling payments and maintaining their own experience for that process may opt not to go the Paypal route at all.