Mal Duncan eventually got an inferiority complex about his lack of powers (he shouldn’t have. He was more useful than Aqualad).
Fortunately, a handy angel dropped by with a magic weapon. Just because.
The shofar was a real “deus ex machina”, doing different things as the story called for it (sort of a proto-Tyroc).
I figure someone was at High Holiday services and said “hey, what if we had a shofar-powered hero?”