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From Odwiki

In Houdini's geometry, there is a distinction between "Point" and "Vertex", largely for GeometryAttribute's such as texture uv's. Another common vertex attribute is the creaseweight attribute which is used for SubdivisionSurfaces.

Where Houdini calls it "point", other software packages may call it "vertex". A single point in Houdini can be shared by other connecting primitives. Suppose we have two polygon quads which share a single edge. Then we have 6 points. There are two points (on the common edge) which are shared by the two adjacent polygon primitives.

Unlike Point, vertices of one primitive in Houdini are not shared by other primitives. Using the example above where we have two polygon quads sharing a single edge, there are 8 vertices: 4 for each polygon primitive.

Vertices are what allows one to have texture seams on the geometry since the uv's can have different values on either side of an edge. If we had created a Point uv attribute, then no texture seams are possible since there can only be one uv value for every (shared) point. To choose between point or vertex uv's, there are usually corresponding parameters in the UV generation SOPs like the UVPelt SOP (Target Type), or the UVTexture SOP (Apply To), or UVProject SOP (Group Type).