The first time I looked at something like @SignOfficial, I thought it was solving a problem the internet had already more or less handled. Verification exists. Payments exist. Access control exists. On the surface, it all seemed covered. But that impression does not last long once you look at how real systems actually behave.
That is why $SIGN feels more serious when viewed as infrastructure. It is trying to reduce the distance between a verified claim and an action that depends on it. That sounds narrow, but it touches a lot.