Why Is Yul Important?

During the smart contract development process, there are actions, or manipulations which are not feasible for the programmer from the high-level Solidity code. Using Yul, the programmer is given much more fine-grained control over the storage, memory and in some cases calldata layout of the EVM. This control also allows for much more gas efficient code to be written.

The flexibility and gas optimization of Yul are what makes it important.