I love the ease of promoting items in my shop through social media. I love that I can set automated promos as well as manual, because I can promote new listings easily manually and promote my existing listings with the automated version.
Seller Tools has made my life easier. Knowing that our products are being promoted regularly has allowed me to focus efforts on the look of our Etsy shop and branding. We have noticed a significant increase in shared posts and traffic to our shop.
What is the most useful for me is that I can schedule posts for my shop throughout the day. Even if I was sitting at my computer all day long, I wouldn't be able to keep posting for different time zones worldwide.