Hi Per-Erik
An example of a typical application for electrolytic Ni-P would be as an underlayer for electrolytic gold in connector pin applications. The better barrier properties of the Ni-P deposit can allow use of reduced gold thicknesses.
In that case, a solder connection would be made to the base of the connector pin. However, solder joint volume and soldering conditions would be quite different to a PWB component attachment situation.
Regards
Martin