As the author of this app I agree it's pretty cool

I use it every day and am glad that others find it as useful as I do. If you have any specific questions or issues please let me know.
Concerning this - the answer is yes it is capable, but not "enabled" yet. In order to do this you need card emulation and access to the secure element on the chip. The access to this exists, but it's not in any public API. *Who* has access to this is still being worked out as well as the method of access (it changed when 2.3.4 was introduced). Card emulation is also still a "work in progress" according to the official comments from folks at Google. However, they are trialling their own payment system, so they clearly have it going at some level. How public it ever becomes is yet to be seen. For P2P and standard exchange of data/tags they are pushing enableForegroundPush using NDEF messages.