We always install our high efficiency boilers and furnaces with outside combustion air/sealed combustion piping. A hole in the roof with proper sealing is not rocket science. You can easily hire a roofing company to put the flange in place if so desired. And to answer your question directly, combustion air is as important to your furnace as air is to you. Both need to breathe to survive.
If YOU want change, YOU have to first change.
If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!