This seems like a double-edged sword for RIM in that, it's a disincentive to actually develop for the Playbook when they can just create an Android app and market it to both. It seems like a very short-sighted move.
Having more apps offers an incentive for early adopters and end users to invest in the platform in the near term. Eventually, as the platform grows (perhaps as a result of the various app offerings), developers will start creating native applications.
Rim aren't confused, they know there is not enough room for more than 2 device platforms, and they are the underdog.