The fact that having a deflationary money supply is bad, is even debated in cryptocurrency forums is the clearest indication that they have no idea how economics works. ...also, the point of a currency is to act as a STABLE unit of exchange, not some speculative moon-shot. Once these money supply and stability issues are ironed out, and once the scalability problem is solved, I think we might really have something.
Your "fact" encodes a lot of presumptions. Bad for whom?
Moreover, post-civil-war US (deflationary) is a good counterexample, not entirely clear that that era was "bad", hell, a good chunk of the population was emancipated from slavery amidst deflation.