Separating super destroyers and small cruisers is like trying to draw a line between a kitten and a cat. Reality is that they were expensive for what they were but in WW that doesn't matter so much as money isn't an issue.
The USN found that numbers of small DD can't do a cruisers scouting job. It requires range, seakeeping and a larger staff processing the information to forward on. To do this job requires a Gotland or a Arethusa as a minimum.
Cheers,