Do you run multistore website in Opencart? do you run these website as a separate stores or even different domain countries? If yes that's cool:) but by default in OpenCart you can set separate categories per store, separate products and other details but NOT CUSTOMERS.

By Default customers in OpenCart no matter you run in a multistore or no, customers once registered on one store can login to all stores with the same details.

This extensions will change that, Now if user registered at store A, he will be able login just to store A. IF registered to store B then he will be able to login just to store B.

Also that is not all, users can register with the same details (email, name, etc...) to both stores separately.

So making the long story short, now your multistore website will have isolated, and unique customers not sharing login information between stores (if not registered on all stores)

PS: Admin can transfer users from one store to another store if needed in admin dashboard,also can filter out customers list stores