K's are the by-product of an approach that tries to maximize the number of bases accumulated.
In non-froofy-sounding speak, guys generally strike out because they're trying to hit the ball hard. "Shortening up your swing" and "trying to put the ball in play" work great in little league, but in the big leagues, a huge percentage of those balls-in-play become outs anyway.
So if the risk is the same (or pretty much the same) and the reward is greater, take a shot. Try to make *quality* contact.
As for a groundout or sac fly scoring a runner from third, those are extremely rare occurrances. Memorable, but extremely rare. I don't have the numbers, but I'll wager batters have a better chance of hitting a double than of hitting a ground ball or lofting a fly to precisely the right spot to allow the runner to score.