As we said, the challenge in miniature golf design is to make the course interesting to play.
Interesting shots bring repeat business.
Undulations, banking, the size of the greens, the position of the cups, the intermixing of easier holes with more difficult holes to prevent back-up on the course, and a hundred other little refinements, which come only from experience, are the difference between success and failure. On a well designed course a player is rewarded for a good putt without being overly penalized for a poor putt. If you hit the putt correctly it will go in the cup.