Coinbase is directly and indirectly threatened by regulations. The direct threat is that the SEC, China, European regulators, etc. impose much stricter regulations on cryptocurrency exchanges like Coinbase, raising compliance costs until the business fails; indirectly, if the regulations are applied "downstream" to payment processors dealing in cryptocurrencies or to businesses accepting cryptocurrency payments. Another indirect threat is in the form of environmental regulations being more strictly applied to mining operations, which could be fatal for Bitcoin or any other PoW based system (yeah, sure, PoS, PoWhatever, but Bitcoin is half the market for cryptocurrency).

There is also an "inverse" regulatory risk for Coinbase. In the best case (where cryptocurrencies are actually being used as payment systems at any significant scale) cryptocurrencies fill a need that is not being filled by existing banks as a result of regulations on the financial industry. Instead of more stringent regulations being imposed on cryptocurrencies, less stringent regulations could be imposed on the mainstream financial system that would allow banks to create more convenient electronic payment systems. The need for a cryptocurrency exchange could implode if the relevant technologies (e.g. offline ecash) were deployed; you would "withdraw" or "deposit" money in the bank just like paper notes. There is even a case for such a system if banking regulations became stricter e.g. if banks were forced to deploy a less fraud-prone and more privacy-preserving system than the credit/debit card system in use today.