Would you think web push notifications can replace email marketing?
I dont think so.When there are too many notifications, users might feel annoyed. They could choose to turn off the notifications. But, seldom of them might turn off the e-mail notifications as they're afraid of missing the important e-mails.
Email is still our "digital home". So for me email is still a place for transactional things and push notifications is a tool for customer nurturing.
The question is really broad. What kind of email marketing are you talking about?