I took mostly the pilgrim-specific places for the night.
Perhaps not all hotels und restaurants have stamps. You cannot compare the Via Jacobi or the VF through Switzerland to the caminos in Spain and Portugal. There are way less pilgrims. Yet I would say nearly all the chapels and churches, monasteries and albergues have stamps. And there are many on the Via Jacobi, more than on the VF, because a big part of the swiss section of the VF is the mountain ;-)
You will find the most wonderful stamps on the Via Jacobi (even if you stay in hotels for the night) for example at Einsiedeln Abbey, at the Pilgrim Chapel of Haggenegg, at the Monastery of Ingenbohl, at the Chapels in Flüeli Ranft, at the Albergue in Brienzwiler, at the entrance to the Beatus Caves, in the Cathedral of Fribourg, at the Albergue Paroisse St. Amedee in Lausanne (the stamp of the Cathedral in Lausanne is just simple
), etc., etc.
On the swiss part of the VF (which is mountainous but short) the nicest stamps I got at the Abbey Saint Maurice, at the "Sigil. Parochiae Orsiarum" ;-) in Orsieres and of course at the Hospice du Grand St. Bernard on top of the mountain (which is by the way the most spiritual place I have seen in my life.
All the best & buen camino,
Andrea