I think block chains are inherently fine. The issue with bitcoin is that it isn't inflationary. Yes, yes, the supply increases over time, but that's also true for gold, and I've yet to hear anyone call gold inflationary. If a declining unit value is not guaranteed over time then it cannot be used as a currency and just becomes a savings vehicle / speculative asset. This is why all central banks aim for inflation. Try telling the true believers this and they'll reply with something about "sound money", seemingly nostalgic for the gold standard or something. It's rather disheartening.