If you're sitting on the best possible hand in Texas Hold 'Em, and you get your opponent to fold without ever having to show your hand, your hand had influence on how things worked out. Presumably, you wouldn't have been as confident and aggressive with your hand if it wasn't good.
You could, of course, bluff, but that's a risk.
If you have the best possible hand in Texas Hold'Em, and your opponent folds - he's the one who made the right move, not you.
In general, I don't consider preparation wasted effort even if I don't need to call up the actual materials I prepared. If I was better at signaling preparation without actually doing so (read: bluffing), maybe that wouldn't be the case.
Yes - I might have gotten reward 100 by going into the situation with expected reward -12 .. but that would be a dumb thing to do.
That is the nature of acting intelligently under uncertainty - you assume things that might not be true (but probably are).