Why do you need a camera?
Another optional piece of gear. I don’t go on many trips without a camera though. It’s an excellent tool for documenting trips. Phone cameras are amazing these days so that can be a quick camera if you don’t have anything else.
I try to document camp life and my gear as well as the grand vistas and beautiful views. Photographing the details along the way helps flesh out the story. You might even use them to write a story about the trip online somewhere.

Go small and light
What kind of camera you take is entirely up to you. Your phone you are taking anyways is probably the smallest and lightest camera you can find. Just don’t kill the batteries.
An exception to this is bringing a larger camera for better photos. I prefer taking my mirrorless camera since the larger zoom lenses are so much better than any phone.
GoPros are getting to be excellent all around cameras as well, minus the zoom. They also have an advantage of being super durable and mountable anywhere.
Bring a power bank
If you plan on taking a lot of photos, make sure you have something to charge your camera with. Taking photos, listening to music and using a phone for maps will drain the battery quickly.