The reason cats like to shrink their hands may be because it improves their sense of security. The hunched position allows cats to protect their throats, which is a natural defense mechanism for cats. Cats may also like to hold their hands back because it makes them more comfortable. This position relaxes their muscles and helps them stay warm.
Also, cats may also like to shrink their hands because it helps them maintain balance. Cats often sleep in unstable places, such as on chairs or tables. At this time, their hand-wringing posture can help them maintain balance and prevent falling. Overall, cats may like to hold their hands back because it helps them feel safe, comfortable, and balanced.