Location marker: promote to time origin

When right-clicking a marker in the timeline, one option is “promote to time origin”.

What does this function actually do? I do not understand the intent of the wording, nor do I see any obvious effect of selecting it.

It allows a marker to serve as the reference time position for the transport clocks if they are set to “delta” mode (where they measure relative time, not absolute time)

Thank you - now I understand!