Addendum: We are currently considering whether and how the accessibility and temporary closures of via ferratas can be taken over from OSM. At the moment there is little or no maintenance in OSM and there are extra functions for this in renderers such as XCTrails. @Arminus has planned to adopt at least “access=no” in the foreseeable future.
But of course it would be important if these and the seasonal closure times were also maintained in OSM!