Metal Storm's prototypes would be OK as active defense for a tank. Active defense systems are expected to destroy incoming RPGs, missiles, and possibly bombs or artillery shells. An example of a currently deployed system is one that fires a grenade-like thing upward and then has it explode with shrapnel going mostly downward. Metal Storm's prototypes would fit right in to this role.

Another use is as a replacement for the Claymore mine. It's a minor upgrade. The advantage is increased safety for friendly personnel in the non-target directions. Likely disadvantages are cost, weight, and bulk.