RIM's strategy is a dead-end going forward at worst, and confusing at best. They don't want to use Android, and want to use yet another proprietary OS used by just one company (themselves), but in the same time they think a few Android apps will help their OS grow in popularity.
The reason I saw a few apps is because not all Android apps will work with the Playbook or the upcoming BB10 - far from it. Only those applications that are manually repackaged by developers will work. Trivial work by developers, but they also have to bother with this, and something tells me you won't see all the 400,000 or a number close to that, of Android apps working on Playbook anytime soon.
Still, RIM is going to try and push this strategy harder, and right now it's doing that by offering a free Playbook to developers who will repackage their Android apps for Playbook by February 13th. The reason why they give such a short notice is probably because they are about to launch or announce a Playbook 2 very soon.
If they do that, they will need to offer something really innovative, otherwise not too many people will be interested in what's basically another Android tablet without all the advantages and applications of Android, and with more shortcomings, like the original Playbook which didn't even have a native mail application.
At this point, nothing will stop RIM from following their dead-end strategy, until they realize themselves that it's going nowhere. That might take more than a year, because they are only going to have a few BB10 devices at the end of this year, so they might need a whole another year just to realize that it's not working, before they even try to change course. So we're looking at possibly 3 years of RIM without a different course. Things are going to look very tough for RIM going forward.
Source: Blackberry Blog