With this purchase, along with the Skype purchase, Microsoft owns the hardware the user has, the operating system it uses, the calling software and user base.
All that's missing is a mobile network.
It's good for the industry because maybe, finally, it'll be the factor that causes a cross-platform video solution to be adopted by the major players.
Best case scenario for Microsoft is they hold fort and just don't make any money off it. I'd love to hear why you think this is good for them.
If they manage to integrate it gracefuly in their office & collaboration stack, without ruining it as a standalone product, it may very well be a winner for them.
Indeed the challenges are huge but I believe this is the right time for challenges at Microsoft.