Well, in real Match Play there is both: Conceded putts and conceded holes, so it would follow that both options would be appropriate here. Simply having one or the other doesn't really take of the issues of Match Play. For instance, if we simply had a "Concede Putt" option, but no "Concede Hole" option, that wouldn't take care of speeding up play if, say, on Kiawah #17 the opponent landed on the green with their shot, but yours went in the water. You could concede their putt all you like, but to end the hole you'd still have to play until you were on the green and then your opponent could concede your putt to end the hole. Still a lot of unnecessary play there. Having only a "Concede Hole" option doesn't take care of those gimmes that would happen most times, where both players are inside 4 ft with easy putts. You'd both still have to play out the putts to end the hole, so too there is more unnecessary play.
Has to be both.