A53s are the low power (& low performance) 64 bit ARM cores. They are sort of equivalent to the 32 bit A7. A57 is sort of equivalent to the A15 - high power and high performance, so not quite so useful for laptops.

Having said all that:

- I have a Samsung Chromebook 2012 which is dual A15. It still has great battery life.

- What's really going to be interesting are laptops based around the 64 bit big.LITTLE, for example the Snapdragon (either dual or quad A57 + quad A53), where, if the kernel is smart enough, you can trade battery life for performance depending on what the user is doing.

The cool thing about Olimex is that their hardware designs are open-source, so anyone could make a compatible motherboard with the faster chips.