First use of this class of weapon is very rare. Though older iterations are more prevalent they are mostly relics of the Cold War inventory left over in war stocks of former Soviet states. Actual combat use is unheard of. Yet stated use by the Russians and others is primarily anti frogman. With infiltration potentially.
Next demonstrations were done using an FN Scar H. If you read my post is didn’t say M4, M16 or AR15.
This said the primary aim is to produce an anti frogman weapon again. Hence why a .50bmg round. To allow firing from air into the sea at divers. Generally if on an infiltration the diver is probably not looking to fight other divers. If on security around a port the first aim is to defeat divers from the surface. This could be accomplished by bombs or now bullets.