I'm a wild child, I drive without a UK driver's license. I do have a South African drivers license, but seeing as you can buy one for a couple bucks, I'm not sure it counts for too much.
Main reason for installing was a) technical challenge of doing the install and b) it's useful for getting out of the tandem parking bays we have at work where one car parks behind the other, and you either need to do some back and forths to move the car sideways, or ask whichever sod parked you in to move.
Anyway, for parallel parking, park assist would be far more useful.