I am hoisted on my own petard (or kwan dao) in a manner of speaking.
1. I did not want to make beginning students pay for comparatively expensive tai chi shoes (see below two rightmost) when they were just starting out. If someone likes the color or the clacky sound or the feel of the traditional black cotton shoes with red-brown plastic soles (see below leftmost) I am okay with that as an interim measure. I recommend the cheap-o black cotton shoes with white cloth soles (see below second from the left) . Neither black cotton shoe has any arch support, and they also lack laces so the shoes have a tendency to drift around the feet. But they encourage contact with the ground. For a student a class tends to run 2 hours per day five days a week – of course, we are hoping they will practice on weekends. If the student decides after a few months to keep training, the shoes will likely  be ready for replacement anyway. They can step up, so as to speak, to the tai chi / wushu shoes.
2. As many reader will know things are little different for a teacher who might be on his or her feet 6 or 8 hours a day. Unless one has practiced the rarely seen Iron Knees
Qigong, the traditional black cotton shoes (either sole) are torture. In passing, I prefer to change shoes and socks at some point.