Part of what makes me think they are meaningless in general is how much control we exhibit over them when we LD. It's irrefutable that we can control our dreams; some of us here do it almost all the time! So, if we can modify what's happening, is a message being delivered in the first place?

Scientists don't exactly know why we dream, but some have suggested it occurs while our brains sort out shit that's headed into the memory bank.