Feet and toes are not usually as dexterous as hands and fingers but they can grip and hold things. With training and practice they can be like third and fourth hands. Are there any astronauts who make use of their bare feet in this way?
Seems unlikely astronauts would spend much time bare foot in the ISS, for example. There are blue handrails on different surfaces, in all four orientations, where astronauts secure themselves by sliding their feet underneath. You can see the handrails at the bottom left, top right (two on the "ceiling" and more on the right "wall"), and especially at the bottom right, where you can see an astronaut with his feet secured underneath it.
The astronauts wear socks to prevent chaffing while securing their feet underneath the handrails.