How a customer first purchases from your store matters.
If they came in from a friend's referral, they'll likely trust your store and have a positive experience. Even if small things don't go right.
If they clicked on an ad that interrupted their free time, they're likely to have missed some things (e.g. shipping policies) and could be more demanding of your customer service and returns.
If they were a long-time subscriber to your email list, they might know exactly what to buy and all of the benefits for it already.
If a tourist walked into your physical store, shopped for a bit, and then checked out on your POS then they probably won't buy again unless you make your online store really clear or have a process to communicate with them post-purchase.
Same first buying step, but vastly different long-term behavior based on how they showed up.
In Shopify, you'd want to use your sales channels for this. Being able to separate your online store sales from your POS from your advertising-driven sales will let you see the different behaviors.
But sales channels alone don't tell the whole story as they track where the order came from, not the customer.
Instead, Repeat Customer Insights segments many reports by the acquisition source. This is the sales channels used in the first order. These make it better to see cross-channel sales over the lifetime of the customer.
Use cohorts to find out who the best customers are in your Shopify store
Repeat Customer Insights will automatically group your customers into cohorts based on when they first purchased. This will let you see how the date customers bought would impact their behavior.