I like this opcode.
It opens a whole new design space for smart contracts. Anything that requires a callback can use this opcode to pay the fees for the callback. No longer do we need the cumbersome quote + msg.value workflow for stuff like LayerZero.
While it’s technically possible to build this on the application layer, it breaks compatibility with existing routers and onchain superstructures. Additionally, paying via gas allows for transparency and minimal hassle workflows. People know how much they are going to pay. Contrast this with approving and pulling some ERC20 (needs simulation, and fragments liquidity).
To prevent the risk of DDoS via gas recycling, this opcode needs to take a cut of all gas that passes through it. A 10% cut should be Goldilocks.
I have outlined additional advantages of such an approach in a similar RIP RIP-7767: Gas to Ether Precompile