Distance option in toolbar

What is the "distance" for, as in attached? I tried to figure it out but couldn't...

This is part of the tool option bar: https://librecad.readthedocs.io/en/latest/ref/toolbars.html#tool-options

Depending on the selected function, this tool option bar changes. Check the following page:
https://librecad.readthedocs.io/en/latest/ref/tools.html#drawing-tools

But it is also there when I draw a line, circle or ortho line etc... Does it have any use when we draw those? I assume not

See https://forum.librecad.org/Ortho-line-length-tp5720802p5720803.html