Is there a reason to keep any building-making functions that can easily be converted to JSON in mapgen_fnuctions.cpp (i.e. for legacy saves?)

Also I noticed there were two separate fast food restaurants defined- one here in mapgen_functions.cpp, and another in overmap_terrain.json. They are exact copies of each other down to items spawned, but are mirrored along the X axis? I added them both as equally likely instances of s_restaurant_fast overmap terrain, but I don't see why it would be necessary to keep both if they can be auto-rotated.