This kind of construction was needed to make clearance from the trees. Otherwise a lot of interference would result when the wires touched the foliage...especially when it was draping and wet!

Tree trimming for clear communications really must have been a real pain in the A in those days!

Covered paired cable with twisted pairs took care of a lot of that problem (beginning around the teens) as well as the paired cable's physical resistance to storm damage. A lot of the early phone paired cable was had lead covering (sheathing). And these surely have stood the test-of-time since there are a goodly number of them from the 20s (if not earlier) in active (aerial) use by Verizon here in the Boston vicinity.