MarkoH01: Please stop saying "they work offline" since there is a offline mode in steam as well but you still would need to have the steam client running to start the games in most cases.
josh72718: I am so confused right now. But I'll stop saying it. :)
Why are you confused? It is not difficult.
1) Game executable can be started without ANY steam running
=> game should be in this list
2) Game executable can be started only with steam running in background but you don't need to be online
=> game should not be on the list
3) Game executable can be started only with steam running in background and need to be online
=> game should not be on the list
So even if you don't need to be online in the example of 2) you still need to have steam running to launch the game and so such a game should not be on the list. So it does not matter if you can play online only or offline as well - important is if you can play it without running the steam client at all.