It is actually a pretty cool feature and an excellent idea, especially since sometimes leaving water behind can result in unnecessary buildup of gunk and mold, but also in some instances, could corrode the material. This is a feature that apparently Apple could be interested in bringing to the iPhone and iPad as well.
This is based on a patent discovered by AppleInsider in which it seems that Apple is exploring a variety of ways to get rid of waters that might otherwise enter or get trapped in the speaker grills of the iPhone or iPad. Right now most water-resistant devices rely on sealing off ports to prevent water from getting in, but given that speaker and microphone grills are open, this isn’t a 100% foolproof solution.
It is unclear whether or not this is a patent that Apple plans on making a reality, but it could be a rather unique selling point. To date, there are no smartphones that are 100% waterproof, and at most are water-resistant.