They avoid mentioning this being a superconductor because it's not what it is. However having 0 resistance is a typical property of a superconductor, it's not the only defining property. I think the established defining properties of superconductors:
1. They have 0 resistance.
2. They have Meissner effect [1].
Being a topological insulator and only conducting along the edges I think (2) is not possible for this material. It's not like it makes it any less interesting.
I was sure carbon nanotubes matched your description, however the relevant Wikipedia article[1] mentions the electric properties without refering explicitly to resistance.
1. They have 0 resistance.
2. They have Meissner effect [1].
Being a topological insulator and only conducting along the edges I think (2) is not possible for this material. It's not like it makes it any less interesting.
[1] https://en.wikipedia.org/wiki/Meissner_effect