Full chain cases were common in NL, not so much in Germany and in Germany were usually found on very old bikes or Dutch bikes.

Almost all bikes had chain guards, even the relatively small number of derailleur equipped bikes used for commuting. I left Europe in 2002, and except for one 2 week vacation in NL, France and Germany in 2011 haven't been back, so I am not current with popularity of the newer belt drive bikes. I would be surprised if many European commuters would be impressed with the hyped "advantages" of belt drive over chain driven bikes.