Design History Uses?

I can see that this is confusing for a new user.

In more complex models and assemblies the timeline can become quite long and complex and edits can take quite some tome to re-calculate.

Also  when a design is more exploratory and is developed more or less on the fly it can be very liberating to work without a timeline, because there are no inherent dependencies between sketches and  sketches and features and between components. There are no timeline features that fail because a reference is broken.

This might sound a little abstract but it will become clear once you have some practice.