This brief cosmology should help you to figure out what this Advantage can be used for in this setting.

There are multiple types of planes: the outer planes, the “glue” planes that link other planes together, the material planes and the inner planes.

The Outer Planes are metaphysical in nature. They're a place where belief becomes reality and there are many outer planes corresponding to a multitude of views on life. These planes are two steps removed from the material plane.

The outer planes are linked to the material plane via the Astral Plane, which is a plane of pure thought. It is one step removed from the material plane. The Astral has a border that touches the material plane, with a few insubstantial beings living on it that occasionally affect the material plane.

Next comes the Ethereal Plane, a “glue” plane which is the material plane's link to the inner planes. It is a plane of possibility and semi-substance. Illusions can take on physical form here. This is split into the Border Ethereal and the Deep Ethereal. The Border Ethereal is very closely related to the planes it's attached to and all inner planes, most demi-planes and all material planes (the normal planes most mortals live in) have one attached to them. The Deep Ethereal is the limitless sea that the inner, demi- and material planes float in. The Border Ethereal is much like a beach between ocean (Deep Ethereal) and land (the plane in question).

Of notable importance is the Border Ethereal, as anything on it is insubstantial and invisible to those on the material plane. So, for example, a ghost can be attacked normally by a character that has used Jumper to travel there. Used in this fashion, Jumper reverses the normal relationship between substantial and insubstantial. For example, if a ghost is forced to the material plane via Affliction with the Advantage (Jumper) Enhancement, the ghost's natural state becomes that of a substantial being that can shift to the Border Ethereal by using it's abilities. Also, any of it's abilities that would normally be used on substantial targets would work instead on insubstantial targets. The reverse is also true: a material target transported to the Border Ethereal via Jumper can affect substantial targets with abilities that are enhanced with the Affects Insubstantial Enhancement.

The Ethereal plane is one step removed from the material plane. Demi-planes are two steps removed.

Finally, the Inner Planes are those of substance, such as the Elemental Planes (Air, Earth, Fire, Water, Negative Energy and Positive Energy). There are also para-elements and quasi-elements that are mixtures of these. Also of note is the Plane of Shadow. It is probably a full-fledged Inner Plane, but is also sometimes classified as a demi-plane. The Inner Planes are two steps removed from the material plane.