I work for a company in the health-care space. Everything we store has at least one and usually multiple timelines associated with it (for example, a piece of medical data would have at minimum a "when did this happen" and a "when did we know that this had happened"). Being able to rewind/replay history from a certain point and identify everything that happened and why is a fundamentally important thing for the kinds of audits and compliance checks we're required to do.
It means they can provide evidence of offers and claims made at any point in time. I'm working at a big financial services firm that already has a proprietary setup that goes beyond this. Actively logging every request and response (bodies, not just metadata) so they can provide evidence of every transaction made should they ever be required.
This chrome extension is also great: https://chrome.google.com/webstore/detail/memento-time-trave...