A casino operator runs the site, manages player accounts and payments, and...

https://chancessmartperspective.nexorafield.com/posts/why-does-a-casino-add-new-providers-instead-of-making-everything-in-house

A casino operator runs the site, manages player accounts and payments, and decides which games appear in its catalogue. A slot provider makes the game and sets its rules, such as how symbols pay and what features can trigger