Lack of oversight is the main feature, it only scares old women (not even all of them, who would have guessed but my grandma asked about btc in a call a year ago.) and why is deflation bad?
The problem is that it is a prisoner's dilemma situation, where capital holders do not want to be 'encouraged' to invest their money even if it might be a net benefit to society as a whole.
No one invests for a "net benefit to society as a whole." They invest for a return, and you can NPV your project in both inflationary and deflationary environments.