The reason why the imported users do not show up under Woocommerce > Customers is that:
- Users who have placed at least one order will only show up in this section. Newly imported users will be having zero orders. That is, the database (DB view wp_customer_lookup) contains zero records resulting in an empty view.
- Therefore, once an imported user places his/her first order, this view will be populated. Then, users will be displayed under Woocommerce > Customers.