How did Zeus become the important child of cronos and rhea?

Because there was a phophsey, that Cronus' children would overthrow him as ruler of the universe, so Cronus' plan was to swallow every child Rhea had (Hera, Demeter, Hestia Poseidon, and Hades)but Zeus was saved by his mother, the youngest - for who Rhea fooled Cronus by bundling a rock. Zeus was sent to an island for safety, but he went back to make his father, Cronus, regurgitate all his siblings. In conclusion, Zeus was important because he saved all his siblings.