For now Bitcoin and other cryptocurrency is  still young thats why only few people know it
From those people only few trust it.
From those few who trust it, not all of them know how to use it.
For those poeple who know how to use it(or have idea), only few actually using it.

But now the number of people who have knowledge about it was gradually increasing, maybe after 5-10 years it will be part of common knowledge.