Durston’s article shows the ULC, which is no longer made but is pretty much the Fusion. So here is the difference (I think)
Fissure = Tall narrow pots and no tent stakes needed.
Fusion = Short wide pots and stakes needed for alcohol.
Bottom line is a certain height is needed between the bottom of the pot and the stove. To allow the cone to store in the pot the Fusion has to compromise by using stakes, which is why I hated the ULC and am thrilled with my Fissure.

