1) The attackers bribe overseas Coinbase support agents for customer data.

2) They gain access to some Coinbase user's names/addresses etc (no crypto wallets) which can enable social engineering scams.

3) The attackers demand payment of a $20M USD ransom or they will release the info.

4) The CEO of Coinbase refuses, promises to reimburse everyone who might be affected by this and instead offers a $20M USD reward to anyone who helps bring the attackers to justice.

Absolute cinema