When thrown we practice taking a complete straight over so we're not trained to land silent like that. I see now that it is safe. We do the straight over so eventually we learn to counter throw from uke's throw. I'm not sure you can do that from a soft breakfall, can you?
Opps... all this time I've been doing breakfalls that look almost like a mae ukemi. Although we do land on the side, it still entails uke to bend at the waist like he's going to roll. Sometimes, in a particularly fast and high throw, uke might even land on his folded feet similar to the position when you get up from a front roll.
Is this dangerous? I don't understand how you can fall straight on the floor with your back being arched. Wouldn't that hurt your lower back or at the least, your bum?