See https://wiki.openstreetmap.org/wiki/Tag:amenity%3Ddancing_school ... the wiki, unfortunately, is not consistent at the moment.

A place where people dance socially, as a leisure activity, can be accurately tagged leisure=dance. And if that place also offers lessons, then tagging leisure=dance + dance:teaching=yes is likely better than tagging amenity=dancing_school. These places do exist; here's one you fixed correctly: https://www.openstreetmap.org/node/5744528976

A place where people do *not* gather to dance socially cannot be tagged leisure=dance. That would be troll tagging. ( https://wiki.openstreetmap.org/wiki/Trolltag )

iD's suggested "upgrades" are not correct in all cases. They should only be used on an individual basis, after investigating the feature in question.