The sewing machine I grew up on had a knee control as well. I had the hardest time at first usig the foot pedal. I have a knee lift for my Bernina that raised the presser foot. I still can't use it. I revert back to thinking it controls the machine.
I always wear shoes. My feet are really bad, bad heel spurs. I have to wear orthotics all the time. Taking off my shoes to sew is not something I would even consider. My shoes go on before I go downstairs for the day and stay on until shortly before I go to bed.