Can see this becoming the norm everywhere because it’s so easy to implement.
Most car parks now have a QR Code, which links to MiPark, or similar, some allow pay by machine on site where you can pay by contactless, but my experience, and that of many others, is that there’s often a poor phone signal available so either the app times out, or just takes ages, or doesn’t work at all. Lacock NT car park puts bags over the machines at the end of the season, so the car park is free for everyone.
Uffington White Horse car park does have a machine, members are free, obviously, and you scan the QRCode on your membership card and put the printed ticket on your dashboard. RSPB sites are similar and if you’re an NT member you get free entry to English Heritage sites, and vice versa – this encouraged me to go to Stonehenge earlier this year, for the first time in around fifty years!