Unless you pay the social media platform, chances are people won't see your posts. They tend to get mostly hidden, and this, of course, is how they make their money. On the other hand, email newsletters land directly in your subscriber's inbox. Sure, they can delete them - nothing you do reaches 100% of your audience. However, if you look at open rates and click-through rates of email newsletters, they are usually significantly higher than social media clicks and engagement figures.