Sign Protocol starts to make more sense once you stop looking at the signature as the main event.
The more important layer is what happens after an attestation is issued. A record can be revoked, replaced, allowed to expire, or challenged later. That changes the whole meaning of verification. It is not just about whether a signature checks out. It is also about whether the claim still deserves trust at the time someone reads it.
That is where the design gets more interesting.
A lot of people still talk about signed data as if issuance settles everything. It does not. Claims age. Circumstances shift. Issuers update positions. Sometimes the original record remains visible, but its credibility no longer does. Any system built for real use has to deal with that.