So, what's the difference anyway and why does it matter??

Fishpaper / Fish Paper (Electrical Grade)
Fishpaper is the name for the electrical grade of Vulcanized Fiber. Fish Paper has unique properties, including light weight, and ease of forming and punching. Fishpaper is also unique because it is more resistant to heat and cold than comparable plastic materials. 
Fishpaper applications include: Electrical Appliances, Electrical Instruments, Washers, Automotive, Electrical Insulation, Electrical Devices, Gaskets, Fuse Tubes, Circuit breakers, Railroad track insulation, Bushings for motor contacts, Lightening arresters. 

Vulcanized Fiber (Commercial Grade)
Vulcanized Fibre is a hard, durable, chemically pure cellulose product that contains no resin or bonding agents. It offers flexibility, impact resistance, high tear strength and a smooth, abrasion resistant surface. It can be machined, punched, slit, threaded, formed, molded and WOUND INTO TUBES for literally countless applications. 
Vulcanized Fibre can be used for washers, insulating plates, switch and appliance insulation, electric motor insulation, gaskets, automobile parts, luggage, patterns, and many other applications. Its properties include:

High Mechanical Strength 
Excellent Resistance to Heat and Cold, superior to most plastics 
Light Weight, Half the weight of Aluminum 
Excellent Electrical Properties 
Good Arc Resistance 
Excellent Tear Resistance 
Can be Machined with Standard Tools 
Available in Rolls and Coils for easy automatic punching 

The brand of VF that we use is over 2.5X more expensive than fish paper. 
What we use is the highest quality, most expensive form of VF in the industry, period.
Blue Tube 2.0 is not the same as a generic fish paper tube sold at phenolic prices.
Did you know that fish paper tubes are made with a water based glue? Do you really want that in your rocket?

It is not possible to manufacture Blue Tube 2.0 at phenolic prices, period.
However, it IS possible to sell a bluish colored fish paper tube made with a water based adhesive, but it wouldn't be the same thing.