Coinbase is basically the entry point into a lot of cryptocurrencies as it has easy fiat to crypto exchange. When you have this information you can deanonymise

Coinbase is basically the entry point into a lot of cryptocurrencies as it has easy fiat to crypto exchange. When you have this information you can deanonymise most activity on most blockchains. This might go into tinfoil hat territory but it might be a reason Coinbase is of interest to Facebook