Those "covid"-lanes have been painted mainly on main roads outside of towns, where the speed limit is 60 or even 80 km/h. They are not narrower than required by the Swiss technical norms (i.e. they are at least 1.50 m wide). It is really the remaining width for the car lanes that is impacted! 
Their main benefit is indeed that car drivers get more aware of the necessary lateral passing distance. For example, look at this road section where this innovative way of lane painting is even more impressive: https://www.openstreetmap.org/way/682712590 

PS. On that portion of the Rte de Suisse, the lane tagging is debatable and I will check the results of bicycle routers. Maybe I will revert the tagging to cycleway:left=lane...