I agree, dream plots are a pile of nonsense usually. But I get a lot of interesting images from my dreams. Scenes and settings usually, that tend toward SF or fantasy imagery, or an interaction between two people. But plot I gotta work out when I'm awake. My current WIP is based on a dream: I went to see a play/musical spectacular that was totally amazing. The theater was like the reverse of a theater in the round, the audience in the center, and the stage a huge ring all the way around them. Um, and it was on a boat.
Last night I outlined a new fantasy novel based on a dream, sort of. I used to have recurring dreams, and this story would be about a guy having a similar series of dreams, and not being able to figure out if they are real or real-ish or not.
The other day I watched a very unsatisfying season finale (Breaking Bad). I was upset that they hadn't revealed more about WTF is going on. That night I dreamed a continuation of the episode, with a full conclusion. It was satisfying, until I woke up and realized it made no sense whatsoever in regards to the plot of the actual show...