An email list is basically a collection of email contact information from people who gave the required permission to receive updates and promotional emails from a business. In other words, it is a compilation of prospects' or leads' email addresses, which is used in email marketing by digital marketers.
Emails are direct and personal. Therefore, they provide you with the opportunity to create personalized campaigns and original content.
Your digital marketing and SEO efforts may go to waste if platforms like Google, Facebook, or Twitter change their policies. However, you own your email list and it cannot be influenced by the decisions of third parties.
People check their email inboxes several times a day, which offers you a chance to communicate with them whenever you want.
Relevance: Including people who willingly want to receive emails from your business and are interested in your industry.
===Caution: Quality is much more important than quantity in email marketing, so buying an email list to increase your reach is always a terrible idea!