The subtotal (minus VAT) is cheaper if ordered through C&J UK compared to ordering MSRP in the US (asuming US based) but this is only true if fees and tariffs are not added. If you buy shoes from the UK and they are inspected and deemed merchandise in customs, then you will be subject to fees. These fees closely resemble the difference 'saved' from buying in the US. How often this happens varies depending on the carrier used. It always seems like a 'deal' until you receive the bill.
The same argument can be made if you live in a different state and ordered from C&J NYC. If I purchase from the NYC store, I have to pay city and sales tax whereas someone in CT can order shoes and avoid the taxes.
Regarding limiting business, there are many benefits of having a B&M store such has the ability to be fitted properly, handling the merchandise, and developing a relationship with the sales staff. I assume there are enough people who prefer to shop via this method especially if they are less familiar with C&J shoes.
Why does C&J UK allow the sale of their shoes to customers who have a store in their country though? I think it would be more profitable for C&J to "refer" customers to the U.S. store, in this case, and make them pay U.S. prices. If the customer wants to do a custom make up or needs a shoe that the NY store doesn't have, then it should be sourced from the UK, but sold at U.S. prices.