Some might see this as a confusing step, giving people who want Blackberry applications a way to do it without buying a real BB device. In computer terms, however, this is similar as having Apple offering OS X licenses to all computers and not just their own branded models.
From another standpoint, it could make sense as a way to expand their reach by leaps and bounds if they convince enough mobile users to use and get accustomed to the BB environment. The next time you buy a phone you might be inclined to get a BB device or just any phone you like but paying for the software that runs your standard Blackberry features. If not entirely practical on the surface, it is still an interesting approach.