You're missing one of the key points of the OP's post, deflation. With fiat currencies, small inflation is a feature not a bug. If goods cost more tomorrow than they do today, it promotes purchasing today not tomorrow. If the expectation is that each year I will get a raise, it promotes work to get that raise. This increases economic activity. A psychological trick perhaps, but an effective one for the economy.

With Bitcoin et al being deflationary it means that goods will be cheaper tomorrow than they are today. This promotes hoarding, not purchasing. You would expect to get a pay cut every year, not a raise. This grinds the gears of economic activity. You are being incentivized not to spend your money unless you absolutely have to, which is the death knell of any functioning economy.

While there are certainly problems with the current model, cryptocurrency simply makes them worse.