This object reports the feasibility, or best, distance, the minimum computed distance from this router to the destination network for this topology entry, which EIGRP uses to determine the best successor. This is the core metric EIGRP's path-selection algorithm is built on, so an admin comparing feasibility distances across candidate paths for the same destination can understand exactly why EIGRP picked one successor over another, rather than treating the selection as a black box. If two potential paths to the same destination show different values here, an admin would expect EIGRP to have installed the lower-distance path as the active route, using the higher-distance one only as a feasible successor if it qualifies.