What is the difference between "copy" and "copy-equal"?

[1000Fear]

For profile-restore=<...> I know copy is used to restore old values, but I don't quite understand the description of copy-equal in the reference.

copy-equal
Similar to copy, but restore an option only if it has the same value as the value effectively set by the profile. This tries to deal with the situation when the user does not want the option to be reset after interactively changing it.

The URL for this option: https://mpv.io/manual/master/#runtime-profiles

Sorry, I am not a native English speaker, it's a bit difficult for me to figure it out.
Can you teach me in simple and understandable explanation?

[llyyr]

The options set by the profile will only be restored if the current value is equal to the value set by the profile. This is so options you set during runtime aren't undone.

[verygoodlee]

In this case, if you manually change the volume from 100 to 80 while pausing,
copy can restore volume from 80 to 50,
but copy-equal can't, because 80 not equals 100.

volume=50
[test]
profile-cond=pause
profile-restore=copy-equal
volume=100

[1000Fear]

Thank you! exactly what I need.