Ive used various AR apps to see how products fit in physical spaces--like Ikea used to offer. I've also worked on VR projects for car interiors. With VR you really do get a sense of scale and space that you're still guessing at with AR on a phone. I really liked when people removed the VR headset they were surprised to be back in a small room.

Like you mentioned, Ive wanted to scan some spaces to remember them in the future. Last time I looked, those apps werent very easy to find or easy to use.