Where 3DAPI fits better
For an ecommerce seller who wants store-connected, automated fulfillment of consumer products shipped to shoppers, 3DAPI is built for that workflow.
The current Shapeways is oriented to B2B manufacturing rather than being the fulfillment backend for an Etsy or Shopify store, and it no longer runs the designer shops that once filled a similar role. If you sold through a Shapeways shop, 3DAPI lets you sell the same kind of products through your own store.