I think so. Each #safebox has its own nsec. It stores an owner npub, which is supposed to be the npub of the owner. This proposal might be useful for safeboxes that need to be publicly known, for example that they are operated on behalf of an owner (medical clinic) to issue medical records, credentials, etc. This would enable anyone to see that the wallet is properly delegated, anyone who needs to see that the medical record is properly signed and authorized.