I would rather say pressure elongation. The Bourdon effect is about the rotation due to oval section.
I don't think I've heard it described this way before, but that makes sense.
I think of it as the tendency of any shape containing pressure attempting to resolve into a sphere of outward expansion.
It's possible to have pressure contraction, too. Consider the case of a rubber expansion joint bulging outwards faster and then drawing the ends inwards. But I doubt we'll see too many balloons installed as piping components, so it probably doesn't make a presence in this line of work.