SmartWindow trials begin on Karlsruhe tram-train
https://www.railwaygazette.com/technology-data-and-business/smartwindow-trials-begin-on-karlsruhe-tram-train/59914.article
It's definitely convenient to use SmartWindow. But, another factor we should consider is that it would cost a lot to apply the technology to most of the other railways. Even if a new technology is meaningful, it won't be commercially realized.
