I have several schools of thought on this. My preferred school of thought is that mater and energy are interchangeable so the body can be made energy and then turned back as needed.
I think they both exist at the same time but are in the same physical position during waking hours. The obe are the displacement of this energy body during dreaming. Its an interesting concept and part of it gels with me if you look at phantom limbs and the feelings and sense that they are still there that is reported. It seems this energy body may be the stronger of the two in some ways.
.It also means that external energy sources like heat or light can be adsorbed and used as part of yourself when in a non-corporeal form. However, upon returning to the corporeal excess energy is released if not used to increase mass of shape
I absorb energy in the dreamspace and its getting more regular now. Either light or an object light rock will start to glow and vibrate and then turn to light with the next step being my arm starting to glow and heat up. This can spread to my complete energy body in the dream and leave an afterglow on waking for up to a day. Its an awesome experience and used to be spontaneous and really scare me but now I can call for it If I want to
The other school I prefer far less is that the body is a nursery for the conscious / unconscious mind which when capable of truly becoming one will no longer need a corporeal frame to support it.
I think that a lot but not sure about the being one part, theres a tricky bit of timing it that happens at death and how do you live without the body
Oddly this school of thought has also lead me to believe that there are other beings in this form far more evolved than us for some of whom we are food and for others we are servants of a type that they can indenture into a symbiotic relationship of sorts.
Yip might be some other forms, also I suspect there are other parts of us and the us we think exists is a puppet in a lot of ways.
The last school represents a more religious one where you die and the spirit / soul goes on. Please hold back the flying spaghetti monster comments or I'll put a beat down on a fat Buddha.
LOL - unspoken is spoken enough