Funny thing about memory. You walk around you look at things. You experience them. And two or three months later it's nearly all gone. Two years later you remember only things you took picture of plus maybe one or two things that was strong experience (like spilling coffee over some guy).

People record to actually have any persistent memories of the event. Worn cameras will make this easy on you. People don't hold cameras to hold cameras. They do it just because so far it's the only way.