They wanted to get the basics in place before adding all the extra features - primary function I think was their priority when they decided to bring it to WP. The public beta is also a lot more stable than the closed beta (which I was lucky enough to test).
BlackBerry lands feature-light BBM on Windows Phone
The wait for BBM on Windows Phone is over. BlackBerry has brought its pioneering and much-imitated messaging app to Windows, following launches on Android and iOS last year, albeit with the "Beta" label. BBM for Windows looks a lot more like a native app than other BBM ports: it uses Windows Phone pivot views and includes …