With this report you can see the different sources of traffic like search, direct, email, etc. and their associated metrics like revenue, visits and conversion rate. This is beneficial to be able to optimize spend so that more money goes towards sources of traffic that have the best return. But there is an inherent limitation here that is often overlooked: the reason behind the user’s decision to access the site.
You know that a user came from paid search, but why did they decide to buy something to begin with? Did the product they were using wear out and they need a new one? Did a new life event happen that required them to make the purchase? Did they decide to buy after seeing the product used by a friend?
I think it’s important to remember that the ultimate motivation behind the user’s decision to come to the site is unknowable. Data from traffic sources is a blunt instrument at best to figure out how you can generate more sales. Directionally, it’s beneficial to invest marketing dollars to the extent that return on ad spend is efficient at the highest volume possible.  But don’t be deceived because you can (sometimes) see what keyword they used in a search engine, what device they used, what the email offer was, the coupon code used, the product they purchased, ect.; trying to replicate winning scenarios doesn’t always return like a math problem does.
Online marketing is still marketing, not a math problem that can be solved if you could ‘figure out the data’. Customers are irrational and make purchase decisions based on reasons that web analytics data can’t explain. You can see what happened and as a result improve the site’s usability and marketing investment, but trying to increase why people buy is not as easy as web analytics makes it seem.