Is there a problem with using sys.exit() to stop a Tkinter program?
I know normally people use root.destroy() why is that?
I use both. root.destroy() is used to destroy all windows (parent, child) within the root tkinter instance, but it doesn't end the python program. 
sys.exit() stops all active applications used by python. 
In short, if your python code runs a tkinter GUI exclusively and it's functionality ends after the window is closed then use both root.destroy() followed by sys.exit() to effectively end the session.
Can I use sys.exit() to stop a Tkinter program