This is low-risk new-market experimentation for MB.
Little cost to them as far as research/development/testing because it's on an already established platform (Nissan).
MB likely has low expectations as far as sales go, and if they only end up selling a handful of these to high-end ski resorts to shuttle people from the heli-pad to their chalet then they're probably fine with that.
I don't mind it when companies explore options in their line-ups as it means choices for consumers which, imo, is never a bad thing.