I have been using Charter for my ISP for a very long time. I have my email address tied to bill pay. Because I am changing ISPs my email address is no longer valid. I have started sending my gmail address to the utility and insurance companies.
Having an email address that is not tied to your ISP is a good idea, but not the perfect idea. It would be nice if I had an email address furnished by my bank for bills only. If you used the email only for bills, the bank could add another level of security. A bank can have a "permission only" email address. This would allow the bank to block all email that is not already on a white list. The bank knows every month what email you should receive. When you add a utility to your online bill pay, you also furnish the email address it will be coming from. Any notices or changes will always go directly to the bank and no spam what so ever.
------- O'Neil to General Hammond: For the record Sir, I wanted to blow it the hell up.