For a bench gun shooting paper maybe...for a hiking or hunting style rifle...no. JMO.
How many shots do you need when hunting? Honestly...I think bottle guns look goofy as it is (bottles rarely flow with the guns design) add a second bottle in and you have a very unaesthetic rifle IMO...hence why they released the streamline and soon the dreamline...tubed rifles look much better at least IMO. I have 180 cc's of onboard HPA air and 53 cc's of regulated air on my air rifle, which is nearly 1/3rd the capacity of an Impact with 1 bottle...and I've never said to myself, I want a 480 cc bottle gun, let alone a 960-1000 cc bottle gun. I get 16 shots @ 60 fpe, 24 @ 55 fpe, 48 @ 40 fpe, 72 @ 28 fpe, 104 @ 18 fpe. If I need / want to shoot all day I detune the rifle, I've never used all 72 or 100 shots on my lower power tunes, nor have I had to use all 48 @ my 40 fpe tune...nor when I am set at 55 do I use all 24, nor do I use all 16 when set at 60...because I tune my rifle for what the job calls for...
If I wanted a bench gun to shoot all day I'd just tether my rifle to my tank..