I would say it's similar to not using the same password on multiple sites. If you use the same email, once that one is compromised, than all accounts related t

I would say it's similar to not using the same password on multiple sites. If you use the same email, once that one is compromised, than all accounts related to it could be in jeopardy. By having a separate account just for financial purposes, which isn't used for regular emails with anyone, it just decreases the chances of it being leaked.