Campaigns or scenarios.

In my opinion, both are interesting. I didn't vote because there isn't an option for that. Campaigns are like a long series about fighting the forces of hell. Moreover, the campaigns of the expansions continue the story of the original campaigns. If you play through it once as a hero, it's not interesting to play through it again, just like rewatching a series. At least, in the same or a similar version of the game. I am currently enjoying playing through the original campaigns in version 3.0. It's like watching a new version of the series, filmed by a different director. I also enjoyed replaying the Necropolis campaign immediately after the release of version 1.5. The scenario is interesting because everything changes with different playthroughs if you don't manually set everything up.