Cobblestone walls have the same durability as their block equivalents, but are being built from stone chunks. Slightly more labour required (20 vs 14) and beauty debuff (-2) cannot balance the fact that they do not require pretty long and time-wasting stone cutting process, making the cobblestone walls an absolute choice for the early-game defence structure building material.

25 to 30% durability difference in favour of the block walls should be a good point, placing cobblestone walls into the niche between wooden and block walls.