They are using it:

Other than the page size issue, FEX and Rosetta are comparable technologies (both are emulators, despite what Apple marketing might have you believe). Both FEX and Rosetta use the unique Apple Silicon CPU feature that is most important for x86/x86_64 emulation performance: TSO mode. Thanks to this feature, FEX can offer fast and accurate x86/x86_64 emulation on Apple Silicon systems.

From: https://docs.fedoraproject.org/en-US/fedora-asahi-remix/x86-...