One of its virtues is that it has no physical existence.

That is because you're confusing the physical existence of an item with it's value.

What use is a weapon against something that has no physical existence?

Many times this act helps a spirit to realize it is no longer a part of a physical existence.

And I can't even climb my way up to mere physical existence.

And it was the only physical existence the Terror had now.

The levels above are mainly inhabited by people in physical existence.

I believe the next level beyond them has no physical existence in space or time.

If nothing else, it was hard to think of effective sanctions against someone who did not have a physical existence.

He was suddenly certain of nothing, not even his physical existence.