Better Understanding Level Streaming

Could someone provide a conclusive understanding of level streaming? I posted a a few questions based on my readings and watching a tutorial but I may have missed the mark. My impression was that level streaming would help my team conserve resources by working on specific areas of the level without having to load the entire (large) world we’ve created.

Below is the link to the posting I made, could someone answer my questions or tell me that my perception of level streaming and how I think it works is either right or wrong. Thanks in advance.