Plastic wine glasses

I bought these plastic wine glasses on a previous trip to Tokyo and brought them with us on this recent trip.The alternative would be to bring a couple of glass ISO glasses, but that seems to be more breakable. However I had seen some full size plastic wine glasses on sale, looking rather like Riedel glasses in shape and size and even with a proper rim (not a rolled one). Of course I haven't thrown it around to test its breakability (or lack thereof) but it seems that it could be answer to picnics and even moveable feasts. The problem with bring these on one's travel is luggage space, so they may not be the answer to not being able to drink from "proper" glasses whilst on vacation.