This is a psychological question as well as a comfort one. Either wearing shoes or sandals gives me just a little extra feeling of security. If I were to go to a new resort, for example I might feel a bit more at ease with sandals on, at least at first.
I tried to go an entire day with no shoes, sandles, flip/flops. Wound up with blisters and burns along with small stickers (thorns) embedded in my feet from paved surfaces and plants in the "grassy" areas. So now if I'm around my own home, in or out, I usually do not have shoes of any kind; unfortunately I do have to wear clothes outside but not shoes. But, if I'm going to be walking on a paved surface anywhere except my garage or driveway or if I'm going to be walking much in fields at a nudist resort, shoes are a must. I don't want any more foot injuries and don't think wearing shoes or any other article of clothing is a violation of being nudist. For example if you have been out in the sun too much and you're starting to get into the sunburn arena, it's only smart to put on something to protect yourself.
I tend to wear sandals as I have the incredible ability to stand on sharp objects with bare feet. Footwear also makes it a lot easier using a spade in the garden. Swimming at the Kiwiburn festival I went in with my sandals on raising a few eyebrows, but at least I didn't stumble in and could get out without stumbling out. Most festival goers were naked at the river, swimming togs were quite unusual.