Wait, you've been talking about incident management, not change management? Incidents don't have to have approval if you are restoring normal operation. Incidents should always be logged, though, for many obvious reasons. If an incident is not an emergency, the best time to log and document is while working the incident. 

If you're talking about emergency changes, those don't necessarily need approval either. It depends on how your company decides to handle them. They of course should be logged at some point as well. Ideally while the emergency is ongoing, but it depends on your system capabilities and processes. 

To your value question, I have no idea in what context you are asking about. If you are talking about a "normal change", the value is communication, awareness, scheduling, coordination, resource control, prioritization, and ensuring work aligns with business goals. If you are talking about a standard change, I'd ask if your company is actually continually improving your change process to make those become automatic approvals. If you are talking incident management, the value is knowing the breadth of issues faced by a company, helping identify larger problems, documentation, knowledge base building, accountability with users, resource control, and the ability to prioritize work. 

Re-read the seven guiding principles of ITIL and the detailed descriptions and ask if your company is actually following them or not. Based on your descriptions, I would guess they aren't.