If you're building your first e-commerce store, you might think that getting a lot of traffic to your site is always good. While traffic is usually good, it helps if you can figure out whether your traffic is actually buying. When you send e-commerce data to Google Analytics, you can figure out exactly which traffic is buying. You could see that users from Facebook typically spend $5–10 whereas users who come from your newsletter spend $50–100. Now that you have the numbers, you can make more informed decisions.

This is one of the steps that I recommend for every single e-commerce store. Even if you don't plan on using the data, it will only take a few minutes to set up. Moreover, if you decide you want to use the data down the line, you will have a huge backlog of data.