Indeed, phenolic tubing is expensive - and flat sheets of phenolic based plastic are also.
Tubing is always the most expensive form, for any material.
The paper based material is brown and shows no visual texture. The canvas based material is a honey yellow color and clearly shows the canvas texture. Now there is probably a fiberglass based material as well. The paper based material is very brittle - I would not recommend it for a telescope tube. A blow that would only cause cosmetic damage to an unfinished Sonotube could seriously damage a paper based phenolic tube.