First a quick run down on similar experienes so you can compare the differences:
Astral Travel is when we are able to deliberately go outside of our own physical selves and travel in the Spirit Realm.
Astral Projection is when we are awake and conscious of where we are here on Earth, and then we send forth our Higher Selves outwards into the expanse of the Universe to view where someone or something else is, or to deliberately travel with our minds in our Higher Selves, but we still are conscious of who we are, where we are while here on Earth.
Duality Existence or Bi-Location is where we are now sensing a change in the way we now are within our abilities and our next wavelength up is now linked to us. We then are able to sense more of a permanent link within us to that which is the higher realm, and we are afforded the privilege of being able to Astral Project permanently within BOTH Realms, (here on Earth and in the Heavenly upper Realm dimensions). We can sense and feel this wavelength alteration with our ability to have this dual existence, as our Heart Chakra is the direct link, so it is important to not overuse it otherwise you will tire out your Heart Chakra and could cause some minor damage. That damage would be where you strain your heart wall muscles, and perhaps raise up your BP rate. Other than that it is all right to be doing this dual existence as long as you don't overtax yourself or misuse the ability granted. What would be the benefits? They would include the abilities of firmer contact with the Spirit Realm, more contact and longer time of contact as well, since you are partly on their plane as well. Usually along with this type of existence comes with it your sensing their energies much clearer and can feel objects there in the Spirit Dimension, even taste foods there and sense the flavor, texture, etc. So you are in essence becoming your Higher Self in both dimensions.
If a person is being taken out of their body or pulled up into the Spirit Realm, this would be Astral Traveling. Since the situation primarily is that you are having this event not under your own control, since you are not doing it yourself, it is one of the Angels or your Spirit Guides accomplishing this.