I can see some upsides to this and some downsides to it.
Upside:
Seller Requires Immediate Payment (for items over £xx.xx)
Downside:
Many items are low priced on here so the option wouldn't be eligible in that instance
However I noticed people are saying 'Buyer requires immediate payment' correct me if I'm wrong but if a buyer buys something from a seller, why would that buyer require immediate payment? surely it would be the 'seller requires immediate payment'?