I actually knew someone that had some physical Ginnies. They were great until rates started dropping ... and thirty year paper came down to "paid off" WELL before their time.
I used to spread Ginnies v Long Bonds ... made a pretty penny doing so.
I always though that T-Mac had its roots in stocks. I did know some bond daddies that T-Mac recruited in 1981 ... Those guys swung some pretty big hammers - heavy hitters. That's all that I knew ... which ain't much, if anything at all.