Although sending emails is plain sailing, but when it comes to sending emails to the targeted audience you may end up landing in their spam box thereby, entitled as spammer to send emails to the target audience without getting into the spam list of the users.
Who would like to sit in front of the computer and keep on sending the emails a whole day long? Over and above that will take a lot of time and efforts in order to send the emails to all the subscribers one-by-one. And honestly, no one’s got time for that.