If an organisation uses paypal instead of their own merchant account, I think twice before buying. Is there a reason the people can't get a merchant account, and if so should I be worried by it?
There is also the legal angle: if I pay more than £100 and less than a vast amount directly then the bank is jointly and severally liable for the fulfilment of the contract. If I use paypal instead then I don't get equivalent legally enforcible rights.
If any proposition looks financially challenging then a bank being jointly liable for any loss is worth quite a lot to me. I also know banks have fraud departments that can make who just ignore you take their end of a contract seriously. Can anyone say that about paypal?
That said I am one of those strange people with a mobile phone without a touch screen, camera, bluetooth, data calling, tethering, web browser, java, 3G, LTE or almost any other feature you might be expecting. Phone calls and text messages on the GSM frequencies is use where I live work.
 Banks reclaim the money for refunds from merchants who have very few rights when this happens.