The whole "BTC is the future of money" ship has sailed a long time.
As the financial system is set up right now, Bitcoin has a lot of potential to reduce friction. For cross-country payments as well as for buying coffee:
Speed, fees, finality.
But the lightning network will have to mature first. We will see if the global financial system evolves faster than the Bitcoin ecosystem. I would expect Bitcoin's ecosystem to evolve faster.
As for Lightning being unreliable and slow - I don't see a technical reason for it to stay this way.
What do you consider a "better-designed currency"?