As ZK is becoming more mature and widely adopted, BLS12-381 is emerging as one of the most popular and widely preferred curves, in part due to its high degree of both efficiency and security. It’s been chosen by Ethereum as the curve for the KZG commitments for dank sharding: https://ceremony.ethereum.org/
Today, developers aren’t able to employ this curve for ZK-rollups or other ZK-applications because the precompile doesn’t exist in Polygon or Ethereum. Adding support would allow for flexibility in the curves that can be used by ZK-protocols. A similar proposal exists for Etheruem that, though stagnated, is likely to be included in the near future in response to the dank sharding choice: EIP-2537: Precompile for BLS12-381 curve operations