The usefulness and game-changing property of the compatibility to me is that you can buy a phone from a small startup with its own operating system and UI and still have access to applications while you wait fot the number of phones to grow and for Skype et. al to port their stuff to the native environment. Without that you wouldn't necessary buy the phone and the conpany would have a much harder time to succeeed,
Also it is good to have a way to run more exotic apps that it does not make sense to port to a less mainstream environment.
I'm Finnish and has used Nokia Communicators since the 90s and my previous phones was an N9 and a N900 so the main attraction is the native environment as a continuation of Mameo/Meego and the company itself. Thankfully there is still some Finnish companies who seems to understand how to apply 'Management by perkele' :-)
Also it is good to have a way to run more exotic apps that it does not make sense to port to a less mainstream environment.
I'm Finnish and has used Nokia Communicators since the 90s and my previous phones was an N9 and a N900 so the main attraction is the native environment as a continuation of Mameo/Meego and the company itself. Thankfully there is still some Finnish companies who seems to understand how to apply 'Management by perkele' :-)