JBQ shares his opinion on 64-bit mobile devices

> In the immediate future, this will make zero difference for consumers. Applications that ship today will continue to be compiled as 32-bit, so that they can run on all the other iOS devices as well.

Actually, applications that ship today (well, in a week) can be fat binaries, compiled for both 32- and 64-bit. Apps should see a performance boost from this, though in most cases it's probably negligible.