I used to work in a very very large well known hotel, ozone machines were only used to remove cigarette smells from guests who broke the rules.

And no one can be in the room while the ozone machine was running. They even had auto-shutoff timers so you could retrieve the machine after it had turned itself off and the room air was breathable again.

It takes several hours to run. This isn’t something you do to every room every time.