In non-Supernatural world nightwalking is generally thought to be a sub-ordinate gift to OOBE (Out of Body Experience). The progression generally goes dream awareness (remembering dreams in a variety of ways), lucid dream awareness, "lucid dreaming", "astral projection" ~ OOBE. Some people put astral project and OOBE together and some people believe that they are two entirely separate things, but that is beyond the scope of this paragraph. From this progress, one can see that the above established progression system is focused around the dream / meditation world.
Uriel Entering Dean's Dream
Didn't Uriel enter Dean's Dream in a Episode during Season 4 which resulted in Dreamwalking situation shouldn't that episode be added to the Episode List on the Dreamwalking Page.
Yeah you're right.