My idea was more of a replacement for a shopping list, not necessarily one's memory. To do diffs on physical environments may help situations where the contents

My idea was more of a replacement for a shopping list, not necessarily one's memory. To do diffs on physical environments may help situations where the contents of the diff matter. Maybe you don't have to catalog, maybe it can just show you what shape appears to be gone. Yes, there are many practicalities not ironed out, but I could see it being useful.