Yes driving barefoot without wearing shoes is dangerous and I can say that from personal experience.
One summer I decided to take my shoes off after work and drive home and on my way home I went to step on the brake pedal to suddenly stop and my foot slipped off the brake pedal.
I was unable to stop in time and rear ended a vehicle in front of me that had suddenly stopped.
It wasn't illegal to drive without shoes but it certainly was dangerous and I will never drive a vehicle without wearing shoes again.
It feels nice to take your shoes off but you should wear shoes when driving which is a serious thing.