Of course, for any of that to matter we'll need a 64-bit capable version of Android. Oh, and some apps, too. Making Android itself 64-bit capable is pretty straightforward, though.
It's based on the Linux operating system which has itself been 64-bit capable for around a decade, and on top of that Google has recently taken to inserting a tantalising little 64-bit icon when displaying the list of new features coming to Android at press and trade events.
So, 64-bit is clearly on it's way, although it didn't land with KitKat (although whispers are that it might support it. But really, that detail isn't hugely critical. You need both hardware and software and you can be confident that when the first 64-bit phones appear, Android will be ready for them.
Whether the application ecosystem will be is another matter. For apps to fully benefit from the new 64-bit architectures, they'll have to be recompiled. In a lot of cases, that will be a fairly trivial job for developers. But the fact is the jury is out on how quickly that transition will happen as we're still yet to see a definite reason for it.
Should I care about 64-bit then?
If you're wondering about any downsides to 64-bit, well, it's a question of complexity. Inevitably things like code size and DRAM fetches get bigger, and 64-bit programmes simply tend to be larger and so more computationally complex.
The issue here is power efficiency. Any time you increase performance, you'll need to improve performance-per-watt to maintain battery life. So 64-bit isn't really any different to other performance-boosting options. Add mores cores and all things being equal, you use more power.
So, here's the upshot. 64-bit phones and tablets are heading for the mainstream and fast. Apple is already there and some time in 2014, the first 64-bit Android phones will appear. By late 2015, it's likely most or all high end tablets and phones will be 64-bit.
A few years after that, nearly everything will be 64-bit.
And while it may be some time before we truly need the increased memory addressing that comes with 64-bit, the broader performance improvements that go hand in hand with the new chips will be very handy in the near future.
In that context, Apple probably doesn't deserve a kicking for bigging up 64-bit or making the move too early. There's no doubting its 64-bit A7 chip is a powerhouse that delivers awesome performance you can use today.
More to the point, the hardware has to come first and lay the foundations for this brave new world of 64-bit phones and tablets. Build it and the software and apps will surely come. We therefore welcome our new 64-bit overlords. You should, too.