Forward / backward tagging

Triggered by a mapper who puts tags on highways as “motor_vehicle:forward=yes” or “motor_vehicle:forward=no”:

Does the tagging ‘yes’ implies that that highway is closed to motor_vehicles in the other direction?
If not, why then tag this at all?

And, if ‘no’, does this imply that that highway is open to that vehicle class in the other direction? If not, why then not the general motor_vehicle=no?

And we have the broader used tagging of oneway:*=yes|no(default).

I received a motivation that - probably by Mapillary pictures - he could only observe one end of the highway, so…

What is your opinion? If the ‘oneway:*’ scheme has all the functionality, why then?

I would say that oneway:* is the more common way to map this type of restrictions. Did you contact the mapper to ask why they do not use the oneway:* tag ?