If I understand well, the new feature “Lazy loading offset option” is directly related to the activation / disactivation of the feature “Lazzy loading for images”.

If the lazzy load is not enabled, then there is no relevancy to display the offset option.
If the lazzy load is enabled, then there is relevancy to display the offset option.

Also, the position of the offset option is not at its best location in my opinion. See attachment.