[phantomread]

It also helps when trying to put limits on greedy users or maintain a ban-list. Attribution is also important, like you said. Granted, an abusive user could just keep creating new keys, but if they require something like email verification then it's a little bit costlier to circumvent than nothing.

EDIT: Based on other comments, there's no email verification.

[cmeacham98]

There isn't currently, but they could add whatever requirements to generate new keys in the future they want. If they didn't have keys that would break every existing client.