I think its unfair to dismiss the currency aspect of bitcoin. The use case for the developed world is 95% speculation 5% buying contraband online however, for people in Venezuela[1], girls learning to code in Afghanistan[2], or women in Saudi Arabi who can't legally open a bank account, Bitcoin is solving problems that under banked people have now. Of course the ecosystem needs to mature so grandma can use it safely, but that will come with time.

[1] https://www.cnbc.com/2017/08/24/bitcoin-mining-is-popular-in... [2] https://www.coindesk.com/how-bitcoin-helps-afghan-girls-achi...