If the analogy you're drawing is mp3s to money, it's not a good one. Money has been digital much longer than music; SWIFT was formed in 1973. [1] The MICR E13B font, the machine-readable numbers seen at the bottom of every check, was adopted as a standard in 1958. [2]
Further, since cryptocurrency's use in actual commerce is a rounding error, I don't think cryptocurrencies are even at the mp3 level yet. To be useful to most people, cryptocurrencies need to be turned into real money, which makes enforcement easy enough. It's especially easy here, in that ICOs are big public launches.
Really, anything taking significant amounts of money from non-accredited investors needs to be quite public, because individually they don't have much money. Which again, makes enforcement easy. And also makes it clearly under the domain of the SEC unless they are careful to exclude American investors.
[1] https://en.wikipedia.org/wiki/Society_for_Worldwide_Interban...
[2] https://en.wikipedia.org/wiki/Magnetic_ink_character_recogni...