In order to get the out, you need 5 things to go right. If anything goes wrong, the runner is safe. The pitch has to be catchable. The catcher has to handle it cleanly. The throw has to be accurate.
Baseball is about outs.
If you record them more efficiently, you win. I've found a lot of kids are used to the idea of the automatic steal of second, so they trot down there. The result is your C, 2B and SS don't learn how to handle steal situations well. It wastes the time of the manager in the majors who now has to teach this fundamental skill. Also, when you routinely contest the steal, you r chances of picking off that runner at third increases, either via a direct throw, or a pitcher cut-off.