Obviously, if you can avoid being commoditized by maintaining your own software platform, that's great. I just don't see that RIM is bringing anything to the table with their OS: http://apps.ycombinator.com/item?id=2263882
This way they can build differentiation full Android stack integrators can't. That, of course, if QNX proves a better environment than Linux.
This is, BTW, the same strategy Microsoft adopted eons ago, when the de-facto standard business OS was CP/M. It was very easy to port your programs from CP/M to MS-DOS (thanks, in no small part, to Intel making the 8086 asm-source compatible with the 8085) and that allowed them to have a reasonable software base from the start. Unfortunately, for CP/M, this was a one way road - it was not as easy to port back.
If Rim can manage a superset of Android, they may have a fighting chance to differentiate themselves.
At this point, I'm more concerned about their competency than their strategy.
OTOH, I believe the Apple app store TOS would prohibit any in-store app to be distributed in any way other than the store, so, there is one interesting contractual risk.
The Android stack, kernel excepted, is Apache-licensed (thanks, davidw). To graft Bionic (or any glibc workalike) on top of QNX should be a walk in the park in comparison to build a full competitive stack.