Absolutely! Delves help to detail out select locations of adventure. Dungeons, caves, ruins, forests, swamps, deserts, etc, all can provide session of explorations that work the same. Even just general ruins can provide a good session or two. Done well, they provide a nice limited sandbox for the party to play in, as they can choose how to proceed while staying within the DMs prepared area.
That's not to say that every adventure should be a delve. For our group, I'd say about 1/4 - 1/3 of adventures are delves. However, I'm currently putting together a megadungeon for one-shot play when the other DMs have to cancel, which would be entirely a delve.
That's not to say that every adventure should be a delve. For our group, I'd say about 1/4 - 1/3 of adventures are delves. However, I'm currently putting together a megadungeon for one-shot play when the other DMs have to cancel, which would be entirely a delve.