First we have to also deal with DC Comics' Captain Marvel (Shazam). Secondly, Ms. Marvel would refer to her pre-2012 (?) character/costumes. Aliasing would remove the distinction for anyone who wants to find those pictures.
Regarding your example, Misty -> Kasumi is English (translation) -> Japanese (original), so that's a different thing altogether.
Given that Captain Marvel is the code name that's been used by several Marvel characters, and as Kikimaru mentioned also by a DC character (who dates back to 1939), I see no reason to prioritize Ms. Marvel for an alias.
