There once was a time when various comics companies would just toss random characters out there and see what stuck. While the Silver Age version of characters like the Flash and Green Lantern first appeared in DC Comics’ Showcase, that particular comic was initially intended as an anthology to introduce new characters. In point of fact, the first character to be featured in Showcase was a firefighter named Fireman Farrell. He got three short stories in that issue and as near as I can make out was never seen again.
As a digression, Farrell’s last story featured a national news TV crew following Farrell and his company around as they fought a fire, but that was to cover a story about a local (and apparently unpopular) ballot initiative to give the firemen a raise so they could do stuff like send their kids to camp (that was treated as a tragedy). One woman interviewed said the teachers deserved a raise first, and a home viewer decried that woman as “stupid”. I sure would like to know why wanting a raise for a nation’s educators is stupid. Or why a local ballot initiative was national news. I guess the point is I don’t miss Fireman Farrell.
But that “let’s see what works” approach is my best explanation for the Sea Devils.