My 1.2 cents worth.
A low power scope(less then 4 power) is faster then open sights in most cases and way ahead in poor light.
If your eyes are no longer 20/20 a scope wins again.
A scope will show you a half inch branch between you and your target. Iron sights do not unless it is right
in front of you.
If you got a handgun, it works good on snakes.
Even with your 4 power scope IMO that should be what you take.