MeFi member parliboy gives a good explanation why putt-putt golf competitions are actually pretty serious and the courses are somewhat standardized.
Things don't always go perfectly according to plan. Moisture in the carpet affects traction and skidding. And skidding plays a much larger role with a banking shot, with a decent angle, because the changed angle of the ball might not be what you want it to be if the weather is off. (And no, you're not allowed to wipe to rain off of the rail; the rules actually prohibit that.) Wind plays a role, like with "real" golf.