I have done a lot of barefoot walking this year and found it really nice. I don't know if it healed any trouble, though thinking of it, I used to have some pain that I did not notice for the whole year now.
Ok, there is some pain in walking barefoot in many areas I tried, mainly paths that are gravelled. Or that creek valley I walked up recently in the mountains. Sometimes one can make awkward movements when stepping on a stone in the wrong way, so people who have weak muscles or tendons should take it easy at first.
But if one has been doing this for a while, I would not expect any bad effects coming from that. So that doc is probably referring to previous foot problems that have not gone away completely yet, so he gives the solution he always gives in that case. The very least I would do in such a case is ask at least 1-2 other experts - or continue barefooting without his crap and then go back half a year later for a checkup and pretend you used the contraptions. I would LMAO if he would say then "see, it is better now thanks to my advice" and you could just bomb him with the fact that you did not follow it
I can imagine however that there are conditions resulting from anything like bad shoes, accidents etc that would make barefooting a bad choice. Like if you have ripped your tendons, having a leg that is shorter or any other more severe stuff.