COHORT CUSTOMERS PER ORDER COUNT tells you the number of customers by number of orders.
Columns represent orders. How many customers placed 1 order, 2 orders, 3 orders, 4 orders, 5 orders, etc.
This is a good way to see how many orders are placed on averaged by cohort. Some cohorts might have a lot more purchases - you can dig into those cohorts by segmenting it by products or location and you can see the differences between different purchases by the segment value (specific location, vendors, product, attribution channels).
Was there specific advertising or deals that create a correlation between the cohorts that have more purchases? = you can segment to find out more. You can look at this by %, and you can understand retention - because if you have a subscription business you will see the pattern for subsequent orders.
For businesses shipping non regularly - every 2 weeks, 3 weeks, 8 weeks, this is a helpful metric to understand purchase count regardless of the time.