The Hilton Club New York (HCNY) is unique. There is no way for people other than owners to book there directly using points though they can trade in via RCI. Owners of HCNY can use their points to book at HCNY or anywhere else in the HGVC system (though booking elsewhere is a poor value since the MFs/point are so high).
Note that HCNY is separate from HGVC with it's own reservation website and requires payment of separate annual dues. Also, HCNY is *not* considered a bHC resort and those who own both HCNY and a NYC/DC bHC resort can't use their HCNY points in the Home Resort or bHC windows of the NYC/DC bHC resorts. Also, HCNY deeds are for a certain number of points, most (all?) of which don't actually align with the point costs for a week in any size villa in any season.