I had a box-full until recently that I shamefully threw out :) Yeah, the pins were also quite strong (harder to snip with side cutters iirc), and square (or hex) because the wire needs to bite into the edge of the pin. You could get away with as little as three turns. They were long because you might typically make 3 or 4 connections per pin, so the height would soon stack up. It is really hard, but slightly possible to wire-wrap directly to the pins of old through-hole TTL logic if you have only one connection per pin. The main problem is that unless you use very fine wire and go gently the torsion will twist the IC pins off.

It's also possible to use a mixed method of wrap and solder to make point-to-point simple digital circuits.