Every cylindrical & conical face has an axis. Temporary axis are those created implicitly by cones & cylinders within the model. You can set the default to either hide or show all temporary axes.
The benefit of this is that you don’t have to create them & you can turn them off as soon as you are done, saving time in the design process.
Control the visibility of temporary axes using one of the following:
Hide/Show Items > View Temporary Axes
View Temporary Axes (View toolbar)
View > Temporary Axes