I've tried using it for gas lines, but it was too rigid for me, and became a pain to use. I now use a mix of braided and thick walled PVC tubing with my push to connect fittings for the gas lines.
If rigid tubing can work for your setup, there is no reason why you couldn't use it. The bev seal ultra 235 was really designed as a beverage tubing, but if you want to unify your tubing to the one, it should work fine.
What are you currently using, and is there reason for you to change your gas line?
I'm currently using Bevlex 200 1/4 inch ID 1/2 inch OD. Thats PVC. I'm reading horror stories of how much oxygen gets into my beer through these lines. It's all theoretical but maybe there is better choice of tubing for gas.