The consciousness of lucid dreaming is a cultural evolution. It's something that we are talking about and learning about, not biological evolution.

Your experience is a dream; so is my experience. This stuff about how the frontal cortex is repressed during dreaming, lucid dreaming presents an obvious contradiction to it. The only difference is sensory input.

Lucid dreaming lets you make use of the dream state that comes to you every night to have a stimulating reality.

Not all lucid dreams are useful but they all have a sense of wonder about them. If you must sleep through a third of your life, why should you sleep through your dreams, too?

Lucid dreaming has considerable potential for promoting personal growth and self-development, enhancing self-confidence, improving mental and physical health, facilitating creative problem solving and helping you to progress on the path to self-mastery.

I'd say that we dream primarily the same way that we have consciousness of the world for the same reason. Basically, that our brains evolve to simulate reality and to control what's happening around us.