its just a ploy to confuse you mate. As long as you are using the hose after the reg then yes you can use it, it doesn't matter whether it's air or co2 going through it.
There are different grades of braided hose, but any sold for co2 can be used betwen the reg and gun on nitro (air).
I know you've had a bad result with plastic hose, but my hose and fittings are without a doubt the dogs bo##ocks. They still give you the quick removal feature of push fits, and guaranteed pressure handling.