You can end up sharing an account with someone associated with some unsavory activity and end up having to explain it.
Plus many sites allow users to view their login and download activity logs which means your private information can leak that way.
Sure VPNs and TORs can help mitigate some of that risk but BMN isn’t for opsec it’s for continence if you already are taking extra steps for opsec you might as well use disposable email addresses for your disposable accounts.