I believe the data is correct.

According to https://wiki.openstreetmap.org/wiki/Tag:leisure%3Dplayground
it appears to be a children’s play area with no additional equipment other than the sandpit.

"leisure=playground" alone might be misleading in this case since there is only the sandpit.
I suggest to add "provided_for:toddler=yes" to make it more distinguishable from a playground with toys/equipment.