I've been using the ropeman one for two years now. It is an amazing tool! now I don't back up the ropeman on the linemans belt. I was using a static line that was very stiff and hard to tie knots in. I just got the tethered linemen rope, which I believe is Samson predator rope. The rope is awesome! when you handle it you can tell it is durable, and it ties into a knot much easier, as a linemen tool for going up and down trees it works like no other. I do tie a knot in the end as a fall back up. A prusik knot would delete its ability to work on a linemen belt .
Now as a rope tether for hanging in a saddle it is a good tool as well. This is the area I question the most in the saddle. Now I just bought the mantis and they use amsteel as a bridge. Is really cool , but what if it failed? One I'm considering adding a second bridge as a back up. What the rope man does is allow you to adjust easier on your tether rope on the tree, yet your right it shouldn't be your only safety! so you could put a prusik above or below it and attach the loop, then hook it to the carabiner.