Yes we are meditating on a deeper level than we all realize in this world. The fact that meditation is a deeper form of sleep we do this subconciously. and this is why we go into a dream like state during the meditation process. There are many ways to reach this level and one of them is through sleep.
Meditation has no meaning other than what we give it. It's not a real state of being. As far as I know, meditating is just clearing your thoughts while you're awake. Sleeping isn't meditating anymore than your "mind" is separate from your brain. Meditating ijust sn't the same as sleep.
I don't believe that we are meditating when we are sleeping. The main reason why I believe this is because meditation is supposed to make you calm and relaxed at all times. When we deep sleep we do have tendencies to have nightmares in which meditation is not supposed to do. We are at peace and dreaming not mediating.
All though, they say meditation helps our sleep and deep sleep. Something about being more at piece with yourself, which allows you to relax better. Other than that, meditation and sleep are two different things. Nothing cures your body more than a good nights sleep. It allows you to wake up fresh and allows people to function better during the day.
First of all, there is no proof that the concept of meditation is even attainable. It is an idea that some people believe. But there is no scientific proof of it or if it is even beneficial. I definitely do not think we are meditating when we are sleeping either since our bodies go through a scientifically proven state of unconsciousness.