They say the Holy Father is using this because of joint problems with his knees. That may well be the case, but I think it does enable those in St. Peter's to see him better. While not as high as the contraption that the Holy Father would sit on as several men carried him in, it is high enough for people to get a better glimpse of the Holy Father. As well, it offers more protection to the Holy Father. I think it is a good compromise on the previous loftiness and not using anything at all.