Perhaps a mock-up to demonstrate adaptability to launch discus grenades? Those would surely have been pretty useless if actually thrown like a discus? - secondary fuses don't come into contact unless thrown with their rims vertical, as that machine seems to be so configured. But the imbalances as they were progressively released!
A device born of desperation, whatever the answer. It would be better with those disks fitted with jet whistles of several sizes and used as a siren. Or slanted to make a fan for dispersing gas. Or almost anything except throwing grenades.
