64 bits. It’s Nothing. You Don’t Need It. And We’ll Have It In 6 Months:

What these processors lacked in raw power was more than made up for by they way they were integrated into Apple’s notion of a purposeful, usable mobile device: Enhanced UI responsiveness, reduced power consumption, obeisance to the unique requirements of media and communications.

The expectation was that Apple would either fail, or produce a “competent” (meaning not particularly interesting) iteration of previous A4-5-6 designs. No one expected that the processor would actually work, with all in-house apps running in 64-bit mode from day one.

Source: Monday Note