The original movie was camp. Having a cute, goofy side-kick is virtually obligatory under these circumstances. There might have been better ways to fill the role... but even so, I still found Bubo a fun character.
Heck, I kinda feel that the new movie won't really be "Clash of the Titans" without him [even though, at the same time, I have to admit it seems they're taking it in a different direction (IE: way more serious) that he probably would not work under... at least, not without SERIOUS modifications].