The patent details a variety of sock-like concepts, "foot-shaped support structures with components such as magnets" which, in a hybrid system, could include "a foot platform components with corresponding electromagnets [...] on which a user may stand."
The purpose of these socks would be to provide touch simulation enhancing a user's AR or VR experience. Haptic feedback is when technology artificially conveys the sensation of touch to a user through vibration or other means. iPhones already feature haptic feedback (using what Apple calls a Taptic Engine) through the ability to have your phone vibrate at certain UI interactions, or when soft keys are tapped.
Because your feet contain an extremely high concentration of nerve endings, the presence of haptic feedback on specially designed footwear could convey a multitude of sensations to its wearer and completely change a VR experience. The sensors could simulate a variety of surfaces, as well as provide force feedback patterns to simulate impact, depending on the virtual environment you're immersed in.
The patent also says that the socks' functionality may connect to and be controlled by devices such as smartphones, computers, and "eyeglasses or other head-mounted equipment worn on a user's head." In other words, if we aren't reaching too far, this may have something to do with Apple's upcoming VR/AR line of products, such as next year's rumored VR Headset and the Apple Glass projected for 2025. We might also have a science fiction-y Apple Lens coming in 2030 or later, according to top Apple analyst Ming-Chi Kuo, but maybe that's still a little too far to get excited about.