Difference: External hacks read information from game memory (like our memory hack) or information from your screen (pixel bots or AI bots) and give commands to your input devices (mouse) or on software emulator of your mouse
Internal hacks read information from game memory, but a lot deeper and interact with game. This allows you to get more functionality. But, you pay for this functionality. Internal hacks in 2x - 4x more expensive then external one.
I don't have any specific statistics.But with both there is chance to get banned. And you should understand this when you make a purchase.
In the current situation in the game: the chance directly depends with your actions and how you use it.