There are differences in depth between tags that can be looped through.
When looping through a table of a web page (e.g. calendars) with a "For Each Tag" step, you must create loops for columns within loops for rows (nesting) because only tags that are immediately under the path set in "Tag Path" of the Finders tab are looped through.
With a "For Each Tag Path" step, all paths set in "Tag Path" of the Action tab are looped through within the path set in "Tag Path" of the Finders tab .
You can hence use loops without employing nesting.
For details about tag paths, please refer to "What are tag paths used in DS finders?".