One reason---rare but existent---for disabling these update agents and background services is if someone is using their mobile hotspot to connect their computer

One reason---rare but existent---for disabling these update agents and background services is if someone is using their mobile hotspot to connect their computer and wants to limit all unnecessary data transfer. There's an economically powerful EU country that has a lot of train travel and not so many trains having great internet access. This was my commute life for a few years.