I came across tapioca flour in the store the other day, and was surprised to see that the carb count is actually extremely close to that of coconut flour.

Here are the products I was comparing:
Tapioca Flour :: Bob's Red Mill Natural Foods
and
Organic Coconut Flour :: Bob\'s Red Mill Natural Foods

I'm curious why people seem to be really into coconut flour, while tapioca flour doesn't seem nearly as popular. Is it more expensive? Less healthy?