I'm interested in these articles you mention, but am having trouble finding out more. Do you remember what they were called, or any details about their publication?
I imagine in those types of restaurants, menus might be cycled-out due to wear and tear more often than due to changing dishes. In which case, the increased durability and water-resistance of this stone-based paper might result in less waste.
http://buzz-plus.com/article/2018/10/29/garbage-shibuya-hall...