If we're going to be fair, we have to acknowledge the history of email over the last thirty years: spam, spam filters, and the "Mark as Spam" button.
Email is what I use to notify my customers of a 25% sale, not to tell them that I'm going to plaster their data all over the internet in violation of the spirit of the service I'm providing. I use regular mail for that.
I’m not sure using snail mail as the default venue for important information is really the smart play here. I check my mailbox a lot less often then I check my inbox and I don’t even open 99% of the mail I get since I assume it’s just junk. I’m a lot more likely to miss whatever you sent me if you had sent it by post than if you had just sent an email like a normal 21st century organization.
I'm very much only addressing the small string of text I quoted; I agree it should have been opt-in since many people don't check their email diligently.
Email is what I use to notify my customers of a 25% sale, not to tell them that I'm going to plaster their data all over the internet in violation of the spirit of the service I'm providing. I use regular mail for that.