Cointracker is only a service for tracking cryptocurrency transactions from what I gathered.  The underlying assets may well be held and traded through foreign financial institutions and could be subject to reporting depending on whether the total values of these assets met the threshold for your client's filing status and depending on whether your client resides in or outside the US.

You will need to find out from your client where the cryptocurrencies were held during the year, the total values of all the reportable specified foreign financial assets (that would include asset types other than cryptocurrencies), and determine if that exceeded the threshold for reporting.

Even if your client does not have a reporting requirement for FATCA, you should also review whether FBAR would need to be filed if the cryptocurrencies are held in foreign financial accounts over which your client has either signatory authority or in which your client has a financial interest.