NO! The algorithm finds all the paths between the start and end faces to order them properly, and so the target mesh must be manifold - at least each face must be joined by an edge to another.

This process will re-order the face indexes, but not the vertexes or edges, so it should not mess up any seams or creases. If you have any UV-specific faces, you should verify afterwards, or preferably run the add-on before mapping faces. You will need to run this after adding any new geometry to the mesh, as new faces will be added to the end of the face index array.

The algorithm needs to find optimal paths through the faces, so it will take longer for higher face count meshes. Expect about 30 seconds for a 10,000 face mesh. This is slow, true, but it is an operation that should only be needed once.