The children don't look distressed - they look happy. Perhaps this will help to develop their walking skills (I believe, from the psychology course I did, that it was said neural pathways form not just in the early weeks after birth but for several years afterwards - and they can adapt to changing circumstances. I'm not sure if I've got it right so if there's a medical person on here perhaps they can elaborate on this). Also, as others have said, it will help to prevent too much muscle wastage and keep joints more mobile.
Anyway, who's to know what developments there may be in years to come. I think I saw something recently where it was said progress was being made in restoring lower body function to people who are paralysed.
All sorts of aids are used for people with different disabilities or following medical events - hearing aids, glasses, prosthetic limbs, breast reconstruction after mastectomies, etc., etc. It doesn't, in my opinion, mean you don't accept people as they are, it is helping them to optimise what they can do.