Where 3DAPI fits better
For running a product business, 3DAPI is built for the workflow Craftcloud is not: store integration, SKU-to-design mapping, and automatic fulfillment of every order to the end customer.
With Craftcloud you would quote and order each time by hand; it is not a store-connected dropshipping pipeline. If the goal is "my store's orders get made and shipped to my buyers automatically", that is 3DAPI's lane.