Not all credal sets satisfy the inclusion/​exclusion rule that characterizes DS belief functions. Also, they arguably combine differently (Dempster’s rule vs conditioning pointwise).
Definitely the right way of turning a DS function into a belief is not the way you capture credal sets, since they are notoriously not idempotent (i.e., for most basic DS mass functions ).
Not all credal sets satisfy the inclusion/​exclusion rule that characterizes DS belief functions. Also, they arguably combine differently (Dempster’s rule vs conditioning pointwise).
Definitely the right way of turning a DS function into a belief