Email list is basically the collection of email contact information of people who gave the required permission for receiving update and promotion emails from a business. In other words, it is complied of prospects or leads with their email addresses, which are used in email marketing efforts of a digital marketer.
Emails are direct and personal. Therefore, they provide you opportunity to create personalized campaigns and a special tone of voice in your content.
Your digital marketing and SEO efforts may go waste if platforms like Google, Facebook, or Twitter change their policies. However, you own your email list which cannot be influenced by the decisions of third parties.
People check their email inboxes several times in 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 reach high volumes is always a terrible idea!