Bitcoin has been the ideal proving ground for investment’s most powerful advice: caveat emptor, buyer beware.

Individuals who lose money day trading a cryptocurrency hyped as a way to avoid central bank meddling can hardly expect to appeal to governing institutions when things go wrong. Watchdogs have intervened occasionally to restrict money laundering. But financial regulators have mostly steered clear.

Regulators are unlikely to sit on the sidelines much longer, and that is a shame. People gulled into putting a small amount of bitcoin into a worthless initial coin offering or persuaded to day trade bitcoin on margin are taught important lessons in trust and security. It is better for the bitcoin naif to lose a little quickly and learn that if an investment looks too good to be true it probably is, than never learn and end up losing their life savings on some wild speculation later on.

Unfortunately, cryptocurrencies are getting too big for regulators to ignore much longer. Aside from a change of heart on consumer protection, there are two decent reasons for them to interfere, both of which would have potentially catastrophic results for the survival of bitcoin and other digital currencies.

The first and most important is the danger to the financial system as it becomes increasingly entangled with bitcoin. Those links are just starting to be developed, with dozens of new funds pitching bitcoin to mainstream investors, while futures contracts will next week open bets on bitcoin to ordinary speculators.