The reasoning for this is that you are having a hard time keeping your temperature correct in a 55 gallon aquarium. Chances are pretty good you are going to have problems with humidity as well. Ceramic heating elements tend to suck the humidity out of the air. You would have a much better time keeping the temperature and humidity correct if you had a 10 or 20 gallon aquarium or better yet a non aquarium solution. Your ball python will not get 15 feet long. Other snakes will and those snakes have specific husbandry needs. Ball pythons do not need as much space as other more active snakes. Our concern as keepers needs to be on giving the snake what it needs prioritized like the snake would. Your ball python wants security. I can tell you from my experience that my snake will choose safety over proper temperatures and humidity. That's why I make sure that my snake feels safe in two identical hides one "warm" and one "cool". If you can keep your temp and humidity proper then sure the more space the better. Nine times out of ten you will spend a lot of time trying and failing to keep a 55 gallon tank proper and your snake will suffer.