[ujuj]

Some people just like tiny keyboards. Moreover, keyboards are quite fun to build and typing on a keyboard you built yourself is satisfying : you have so much choice regarding components.

I think that very tiny boards are not really used by their owners (see the Gherkin board for example), but they still are a lot of fun to build. Just don't take it too seriously.

The OLKB Planck seems to be a nice tradeoff between usability and space efficiency.

[cjbprime]

I think you're right about English tiny keyboards, but Japanese ones seem more potentially useful to input kana.