Most of the stuff is far too thin, and will cut in your skin.
A rope for tie ups should meet some basic criteria:
-it should have a certain thickness, or you risk cuts and concussions if one winding suddenly becomes a little tighter than the others. I recommend at least 6mm diameter, better 8 or more.
-It should not create burns when moving against your skin
This disqualifies for example sisal ropes. Having these on your skin is akin to rubbing it with sand paper.
-Knots should be able to be untied
Some ropes don't allow for knots to be untied, ever. Especially small diameter ropes. If you are doing selfbondage this is plain bad, and even if not, it's frustrating to cut your ropes to end every tie-up.
on the other hand
-Knots should not get loose too easily
after all, if the vitctim can get out easily, it's not a real tie up, isn't it?

cheers
FF