Have you ever purchased a product or service from a company and continued to get marketing material about the thing
you already bought? I know I have, and it shows me that the business is just spraying their marketing budget everywhere, hoping for the best. They're not considering the actions that certain customers have, or haven't, already taken.
It's sloppy, and makes those businesses look second-rate.
A properly built sales funnel with correct email automations, allows you to communicate with your customers individually, based on where they're at in their buying journey. Tailored messages go to different groups of people, based on the actions they've taken within your business. It's much cleaner, more effective marketing, and will make your business stand out from the crowd...helping you to close more deals!