Beware that adding a new conformance remains a potentially source- and ABI-breaking change. Being able to describe the availability of the new conformance allows newly built binaries to work correctly when back-deployed to earlier releases, but the new conformance may still cause binary compatibility issues when running previously built binaries that contain their own custom implementations for the same conformance.
I don't think this particular conformance would be likely to break anything in practice, but if bincompat tests proved otherwise, adding the conformance would suddenly get orders of magnitude more difficult.