Why Mini ITX
Snakeoil OS is based on Linux - as such it will work with all computers hardware out there.
The Snakeoil stock kernel is stripped down to work best for mini-ITX. Why? What is better? That's a rhetorical question that can never be answered because if you think of "better" as a mathematical problem, then "better" has no solution. Every person out there has their own idea on what is better, and what is best. Simply support a request thread in the Support & Troubleshooting section if you want a customised kernel for the motherboard you think is best.
But here here are my 2 cents. Is it better to go with modern state of the art full sized motherboards with CPUs (offering heaps of FLOPs); or go for a low power board and CPU that's stripped down to the bare essentials? Are extra FLOPs necessary? Perhaps it's simplicity that's better?
My answer - simplicity.
The downside of using ATOM based mITX boards is the clear lack of processing horse power. However, it has an overwhelming advantage with it's simplicity. Simplicity not only in the physical requirement to dissipate heat, power supply considerations are simpler too. Less processing speed directly translates to less power consumption requirements.
Less is More