Craftable mobspawner with chains

Craft an empty mobspawner with 8 chains and a nether star in the middle. Listen to me elaborating pleaes:

Another crafting recipe for the nether star is nice and a recipe for a mob spawner too. You are able to mine the empty mob spawner to pick it up. To get an actualy mob in it you need maybe a mob to step on the spawner for the empty spawner to be changed into a mob spawner. If this would be unbalanced and maybe if people abuse it too hard, maybe you are able to craft a mob spawner with an empty mob spawner and a mob head. So you put the empty mob spawner right next to for example a zombie head (which is pretty hard to get) in the crafting table and you will get a Zombie spawner.

But note that right after you have a spawner with a mob in it you cant mine it up anymore to pick it up. Idk if every mob would be allowed, like a bat spawner or something would be weird and parrot spawner and other friendly mobs op, so maybe only spiders zombies blazes skeletons etc would be allowed? maybe only spawners that are already in the game vanilla.

This is perfect for lategame. Creeper spawners for firework for elytra

Zombie for exp and rotten flesh to sell for emeralds

Skeletons for arrows and bones, yea etc.

Hope u like my idea