Then think of it as less of a grenade and more of an indirect-line-of-fire very maneuverable... uhh... missile or something. Do missiles require jet or rocket propulsion? Would an explosive propelled by artificial wings qualify as a missile? If so, then yeah!
For all we know, future infantry can deploy tiny flying UAVs that can hover up high so they can get a vantage point to designate targets that can be killfucked by those Quidditch-missilegrenades that the soldiers can launch indirectly without having to expose themselves.
They can be stuck in fighter planes, or tanks, or other vehicles and releashed to act as countermeasures or something even. Though how one sticks flares into tiny winged robots, well, who knows?
It'd be shit to have a flying, buzzing, winged ball come at you and make your face explode.