I think this is just a question of response delay. The article was published late in 2012, so for anyone using the method and publishing an article by itself, you would have to expect at least 12 months, more likely 18-24, for such a new method to "take off". The method itself is solid and has been tested with simulations and in my view is as good or bad as any sophisticated molecular clock approach, since all these approaches work with assumptions that might not necessarily be close to reality. Any such method has to be used with caution, but on the other hand, in the absence of a complete fossil record for a group of interest, this is as good as it gets. The big advantage of this new method is that it works with much larger datasets, which might also explain why only few papers using this method have been published so far.