That can work really well for systems where you don't need to share your key material very often, or where sharing is optimized for n-key scenarios. SSH isn't

That can work really well for systems where you don't need to share your key material very often, or where sharing is optimized for n-key scenarios. SSH isn't always that. For example, ssh-copy-id by default does not copy over multiple identities. For that reason, I'd personally prefer to import my (otherwise airgapped) key into my secure hardware exactly once and mark it as non-exportable in the SSH scenario.