the economies are not going be receiving all the extra capital created by Crypto's plus many other tangible benefits like superfast seamless global transactions, proper wealth redistribution, elimination of money printing, other negative effects will be psychological imagine thinking your government is so dumb they cannot or will not try to comprehend crypto's, this can have very destabilizing effects an all assets classes as well as causing capital flight, which would be the penultimate effect

http://en.wikipedia.org/wiki/Capital_flight