In Android 7.0, there are a number of expandable quick settings for things like WiFi and Bluetooth. Those toggles still exist in Android O, but the way you interact with them is quite different. Expanding requires you to tap the text instead of the icon.
The text in question if right under the icon—not the sort of thing that looks like a button you’d press. Tapping the icon toggles them on and off. See below for a demo video. Long-pressing does still opens the corresponding full settings page for the tile. So, at least that hasn’t changed.
In some ways, this makes sense. If turning something on or off is all you want to do, this could be faster. However, who’s going to realize there’s even an expanded mode? We’ll have to wait and see if this one survives the beta.