Japan’s ecommerce company, turned MNO, Rakuten, was certainly the belle of the ball at MWC this year, and not just because they are the lead sponsor for the beloved local soccer team, FC Barcelona. The company acquired spectrum last year and is building a greenfield 4G network to convert its existing MVNO business into a full mobile platform, chiefly to drive usage of its digital services, such as shopping and banking, and to enable new applications. There wasn’t too much hype at MWC this year, certainly not on the network side, but there was a loud buzz around this entirely unproven MNO, which is deploying 4G not 5G, in one of the world’s most saturated markets. But the excitement was…