If you are looking to engage new potential customers, leads allows you to organize them into special groups depending on their source (where they came from). You can then send these special groups through different decision trees that involve different messaging.
For example, folks that click on your facebook ads may need to receive a special type of messaging whereas those that simply filled out a 'learn more' form on your website may need a different type of messaging entirely.
You can automate all of the messaging by pairing Leads with Sequences. To get started, head to Apps and Integrations > Apps Store > activate Leads.