Using (converted to a curve) edges of a mesh as a bevel object

Let’s say I have a sphere. I select edges connecting two poles and detach them, then convert the result to a curve.
Then I create a path and assign the curve as a bevel object. Nothing is moved and/or rotated. Curve lies in a plane perpendicular to the path. The resulting bevel is flat. Where’s the catch?

Blend file attached.

Attachments

mesh_bevel.blend (476 KB)