FEMA has produced a video explaining this new type of flood zone. The most important to understand is that communities need to build to V zone standards seaward of the Limit of Moderate Wave Action Line (LiMWA). There are no special insurance rates or different requirements between the LiMWA and Zone V (Coastal A Zone); however, if a person builds to the V zone standards in the Coastal A Zone, it may result in lower premiums.
While there aren’t yet any negative flood insurance rates associated with these new Coastal A Zones, the entire flood insurance rate structure is being redesigned for the year 2021; so this may change.
More information on "Coastal A" Zones