Colin L
Tour Winner
If you hit a ball into the rough, find it & declare it unplayable & you opt to go back to the tee & play another, you don't know where the next shot is going to go, you might hit that one into an unplayable lie too. You can't play a provisional ball for one that may be unplayable. However, if you play a provisional which finishes in a good place & it looks likely that the one in the rough will be unplayable you can opt not to look for it. In effect you've given yourself a choice as to which ball to play, if the "unplayable" one were found after a search.
If the provisional ball rule didn't exist you'd have a dilemma. Do you try to extract the ball from the rough? If you take stroke & distance you don't know where it might finish up - you may hit the second one into a worse lie than the first. Having hit a provisional, however, you already know where the stroke & distance ball is. You have therefore gained an advantage you wouldn't have had if the provisional ball rule didn't exist.
To operate the provisional rule fairly, you should perform a diligent 3 minute search for the ball & only use the provisional if you don't find it. I don't know anybody who does that!
But where in all of that lies an advantage - that is, a gain over other players in the field or your opponent, given that they can do exactly the same any time they blast a shot into the boondocks and play a provisional?
I wonder how much longer every round would be if there were a mandatory 3 minute search every time someone mislaid their ball.