SO is it even good for towing a rig off the trail?
I can't answer that question. I can give you the straight up information from the tag you took a picture of.
First off, the CE mark on it marks it certified in Europe.
Secondly, SWL (Safe Work Load) is the same thing as WLL (Working Load Limit) most newer straps have dropped the SWL.
That number is a given, it's listed on the strap. The other given is you multiply THAT number X 3 and that is the breaking limit of that strap.
I don't know how Warn or Jeep or anyone else can qualify that strap at a higher number.
Now, all those numbers are for a vertical load, where weight is constant and gravity is constant. On the trail you're not picking anything up, BUT the additional forces that can come into play multiply the weight load being carried by the strap. You have friction, overcoming obstacles, gravity working for and/or against you while the other various multipliers are added in.
So, use it until breaks, then cut both ends off and trash it.
To be honest, if you want a strap safe for the forces you might be dealing with, you want a minimum 3" wide X 4 ply (layers). Those ain't cheap.
One more thing, that is NOT a snatch strap, shock load it and it may very well break.
But ANY strap you buy that has a WLL or SWL number on it, multiply it X 3 and that's the breaking limit.