When there is a series of promo emails, it would be great to have the goal be able to "listen" for the person in the automation to have purchased the promoted thing. Ideally it would watch for the purchase to happen from any of the previous emails and immediately stop sending the remaining emails that would offer that product.

For example, a 4 email sequence spread over 7 days that promotes "buy product A". Some people buy from email 1. Then they don't see emails 2-4. Other people don't buy from email 1. They get the emails until they buy in email 2-4 or until all the emails have been sent.

Doing it this way would eliminate some of the need to have if/else complexity and be more reliable.