But if you create a cryptocurrency without interest, gambling etc; around 25 % of the world could use this coin.
Idea or not?
Hans Sturkenboom
Holding btc doesn't incur interest. The value of gold and silver go up and down and they were used as currency for over 1000 years in the Islamic world. Muslims in the Sahara used to use seashells as currency because they were non-existent in the desert and required difficult journeys to acquire.
The fiat currency system that's around right now isn't halal; banks that deal in usury, printing non-stop paper with imaginary values, putting pictures of dead guys on those papers, etc. Many Muslim scholars agree that dealing with usurious banks (pretty much all of them), is haram/forbidden except in cases of necessity (ie. Job that requires bank account to get paid, no safe place to store money, etc).
There's a middle east btc exchange already in the works.