If you do a lot of walking around, using public transport etc. And you tend to want to pull your laptop out and use it in places where you maybe don't have a proper desk/table to put it on then having a really small laptop can be really nice.

I remember loving my ~8 inch netbook during university. With virtual desktops it was more than adequate for coding projects even if the best seat I could find was on the floor against a wall.

The added rigidity feels good too, even something really cheaply built out of plastic will have little to no flex, and probably survive being dropped at that size.