As someone who spent his childhood years sledding off of a highway, I can tell you that Flexible Flyers can be steered. Saucers cannot.
Every year, there were injuries, including paralysis as well as broken bones. Every one of them was because some kid got on a saucer, held on for dear life and when approaching an obstacle couldn’t get off in time.
On my sled, I went down head first, screaming with glee at the speed I was getting and when I approached something, I either steered away from it or in worst case, rolled off the sled.
The Snow Wing was my sled of choice. Lower CG like a saucer, but you could steer it.