Your feet don't get sweaty, they are too holey and well-ventilated. That's why I wear them for gardening in the summer, plus they can be washed.
They are ugly, they make your feet look big and wide and your legs look short, that's why I wouldn't be seen dead in them in public, no other reason! However, vanity aside, they are lovely and light and comfortable.
I can drive in wellies and hiking boots, it's backless shoes that cause problems, I have had a pair of shoes slip off and get stuck under a pedal. It was a very hairy moment. I can also drive in bare feet, that was how I learnt.