Not saying you don't follow all the other precautions about using the correct gear to keep control of you vehicle but for more moderate ascents, descents, I have found them useful.
dont get me wrong, they are a good idea, however, if you dont know what your doing, and a computer is making adjustments for your lack of knowledge / ability, they can be quite dangerous if you try to drive without them......
Oh for sure they are usefull but there's a lot who don't know what to do without them and then they don't use them properly, just look at how many people don't really know how to use an auto transmission. No one gets taught.