Benefits of blocking the cart page to only 1 special item per order? e-commerce

I have a client with a particular project of blocking the purchase of a "special item" to only 1 per order.

The user cannot purchase another item in conjunction with this special item, so if the user wants another product, will need to make another purchase?

• What are the benefits of having this?

• This will disrupt for sure the basket-checkout flow?

• User will get piss off?

• How any system can insure to block users with different accounts, or cards but with the same address or even different address?

• or is a good sale if a user purchases the item 10x on 10 different orders?

I totally disagree with this approach of penalizing the user and the experience or the flow because of only 1 item. I don't see any retailer following that technique.

Any ideas, suggestion or own experiences or similar? I'll appreciate all your help.