Now those are BRIGHT arrows!
Aside from the excercise of walking the woods and looking for errant arrows, stump shooting allows you to practice judging distance in all kinds of conditions. THAT in itself helps you during hunting season.
Pick a target.
Guess the distance.
Take your shot.
Step off the distance and chastise yourself for exaggerating.
Chastise yourself for missing.
Look for your arrow.
Repeat as necessary.
You can mix it up by taking another archer along and play a game of "Horse".