Its just a new way on sharing up your addresses
It's also a new way of introducing a man in the middle attack. You'll have to trust a third party not to change your addresses to their own. And trusting a third party doesn't do justice to Bitcoin's trustless design.
Because usually you can't share your watch-only wallets with other people.
Giving the same addresses to different people is a terrible idea. Apart from reduced privacy caused by
address reuse, you won't know for sure who sent you the payment.