> I don't know what they do beyond cancelling accounts.
Unless they've got sophisticated with payment URLs, I don't think they couldn't do that on this alone. These kinds of spams would quickly become a DOS attack on other people's accounts, and some spammers could even be planning to get a refund from a wallet holder they only presume to be gullible.
If the information is of use, it will be filtered into their systems.
You might also be able to report it to coinbase, but I don't know what they do beyond cancelling accounts.