Gaga pits are very common. Can this structure be added as a type of area? They are at most schools where I am and many parks.
I’d use leisure=pitch & sport=gaga, there are already 10 instances of sport=gaga some of which have lesiure=pitch. For those like me who dont know what Gaga is, it is described here on Wikipedia: https://en.wikipedia.org/wiki/Gaga.