Settings > Timeline > Automatically Add Tracks
It only adds another empty track when an empty track gets another clip. It keeps an empty track—audio and video each—ready to receive more without having to manually add tracks.
An empty track also facilitates either rectangle selection or scrubbing.
For a beginner, new, or infrequent user it makes some common needs more obvious. For example, “How do I add music?” Without it, need to learn that you must add an audio track and how to do that. With this, they might see the audio track and it becomes more obvious. Likewise, overlay an image or video on top of a video. A lot of video editors start with a few empty tracks and/or automatically add tracks as you drag a clip upwards or downwards.