Also the ball pythons in the wild have the option to get away from each other if they want to and if they're sharing even a 60 gallon enclosure they can't get far enough away from each other to be happy and still be warm and comfortable.
An unhappy ball python is a stressed ball python and a stressed ball python is a sick ball python. Sick ball pythons get RIs, regurge, and sometimes turn cannibalistic. It's much easier on you and them both if they're separate. If you can't afford a second enclosure you shouldn't have a second snake.