Because it would make for a wonderful portable gaming machine to take to parties. Hate dragging my big ass tower out every time people want to play Gang Beasts.
I prefer building small cases for aesthetics, but I also figure there is less material waste in both production and recycling of smaller parts. It's sometimes hard to find nice parts in small form factor, so this is refreshing!
Smaller is better because it means more power over time. Imagine a current motherboard being built back in the 60s. It would probably be in a building like the size of 10k acres. :O
Smaller is better because even the best laptops aren't that great for gaming. And you can't bolt a desktop to the back of a TV (and have it look nice).
When I was younger I loved big, sexy cases with massive expansion capabilities, even though I rarely made use of them. Now that I'm older I focus more on efficiency, and large cases represent a huge waste of space. Better to tuck all that goodness into a small, well-designed case than waste my desk real estate on techie epeen. I've been excited to build a new mITX system for some time, but have held off for financial reasons. Give me some parts to get me started and I'll take the leap.
Smaller is better for a nice, portable lan rig. It's also better for a HTPC so it's far less obvious as a computer and more of a home theater appliance.
Smaller is better because there's less space for dust collect and that you have to clean out. Smaller is better for most electronics
Smaller is better with a gaming PC because it's not only easier to build a portable gaming rig that you can throw into a carry bag, but you don't have to sacrifice anything in terms of speed for portability.