Cryptocurrencies as it exists today is nowhere capable of replacing currencies altogether. That doesn't mean cryptocurrencies don't have their uses. Almost everything illegal is now being done using crypto.
When people look at bitcoins they think of 2 things.
1. A form of investments that will give fantastic returns in future.
2. A technology that solves a problem.
Its the 2nd point that is more important about but the 1st that will always dominate conversations.
Re 2), the technology's application are very very few, I think. I haven't really seen any except BTC itself, which is pretty bad at being money. That leads to it being "a store of value", and therefore
1) It won't give fantastic returns in the future forever.
When people look at bitcoins they think of 2 things. 1. A form of investments that will give fantastic returns in future. 2. A technology that solves a problem.
Its the 2nd point that is more important about but the 1st that will always dominate conversations.