I use rope halters for everything - I used to only use Nylon, but like other have said I feel if there is a way a halter can feel 'more natural' and like you have more control I feel this is why I preffer rope halters to nylon halters.
Saddlebag, not to get on your nerves, but I agree with what you said, about nerves (if used by the wrong person), however NOT all rope halters have that style - the style you talk about is mainly a training halter, and I do not own one of these.
The blue is an example of the Rope Halters I use and own.
The black is an example of what you were talking about.
There are other styles, not all knotted.