What I realized from your post that how Bitcoin is usable for everyone where a blind man couldn't use it. First of all, this problem is God-gifted, we can't change that by our emotions. Do you think they are just limited to use cryptocurrency? They aren't limited to use fiat? Isn't complicated for them to maintain a bank account and ATM cards? They wouldn't act like a normal human to maintain it. I don't know if there is any easy or special way to maintain such things for a blind man. For that, we can't say fiat isn't usable for everyone. Technology developing day by day, perhaps there would be something where everyone would use Bitcoin once a day. But we shouldn't blame Bitcoin for that. It's just a matter of Technology.