A casino operator runs the site where you browse and play, while a slot...

https://brookssimpressiveop-ed.wordcanopy.com/posts/games-global-vs-pragmatic-play-which-one-feels-more-polished

A casino operator runs the site where you browse and play, while a slot provider makes the game itself. Provider names matter in a catalogue because they help you identify who created a slot and find other games from the same studio