IS IT BECAUSE HE'S SO PROUD OF HIS GIGANTIC HANDLEBAR MUSTACHE?!
I assume it is because of his mustache, since Superman gets his powers back, Captain Comet regained control of his powers (and kicked the villain's ass) and the sinister plan to dominate the world totally failed.
("Amazing New Super-Villain" Starstriker and his amazing new mustache were drawn by Dick Dillin and Frank McLaughlin in DC Comics Presents #22, which is collected in Showcase Presents: DC Comics Presents—Superman Team-Ups Vol. 1).