My beardie, Holly, is in a 30gallon tall with a large ceramic branch where she spends most of her time. Does she need somewhere to hide? She even sleeps on her branch. She also has a large bowl I use for her salads. Lighting is good.
I advise having at least 1 hide (if not more) for a couple of reasons. It provides a place where they can feel secure if they need it. It also provides a place to get out of the light as needed. They self regulate their exposure to UV rays and sometimes they need to get "out of the sun" for a while. A hide is a good way to provide that.
I'm all about offering (suitable) hides, having a glass enclosure with 24/7 exposure is probably stressful long term. As long as your dragon isn't using it all the time (which would probably indicate other problems anyway) giving them the option to feel hidden and secure is beneficial. My guy prefers snug hides, like wedged between his logs or digging under his rock. He never even considers using the spacious caves I've made him.
The range of behaviors you'll see really depends on the environment you offer. Your girl probably spends so much time on her branch because that's all she can do. Pepper spent most of his time on his rock in his previous enclosure, but now that he has branches big enough for him he climbs all over those and doesn't use his rock nearly as much.