In fact, I do not know the disadvantages of this process. But I like it. The last time I visited Kilimanjaro according to the special climbing program. It was one of the best trips. The operator though over every element connected to my relax and enjoy all the time.
You could kill yourself?
You need to climb down once you climb up. If you fall you can die or permanently cripple yourself. You need to find hard rock to climb and a place that you are allowed to climb. It is not a readily accessible activity unless you live some where with lots off rocks and mountains big enough to climb.