It is more obvious when a specific dungeon is named for the contest, like spider or dragon, etc. But for the "Dungeon Diver" that is something else. For that, anything that will yield an artifact or accessory (ring, amulet, etc) is counted toward "dungeon diver" points, it seems. So that basket includes spider, golem, dragon, fire knight. It will not include the Keeps or Minotaur.
It also includes dungeon points for artifacts in Campaigns.
It is important because if you use a champ that gives an aura bonus for "dungeons", it seems to work that way only in certain spots.
That is my understanding. Not everything in Dungeons tab counts toward dungeon diver points.
It is unfortunate that this Plarium game does not say what your points apply to at the conclusion of a raid. Sometimes I see more than one eagle at the end of a raid but it only says "tournament points" for each. Other games would say what tourney event they apply to, such as 1 pt for dungeon diver, and 3 pts for fire knight, for example. You would have to track your points and view the results separately in the contest.