I don't see the benefits in those ebay
things. Personally, I would think any type of contact would just create a vise type hold on the nose and chin, and I don't think your horse would really appreciate that.
There are many different types of bitlesses out there and they all have their pros and cons. Just goolge bitless bridle and do some research.
I ended up going for the Dr. Cooks and I just love it. It has the cross under straps that push the head in the direction of travel when contact is applied. It works with a whole head hug effect which, to me, seems a little bit more useful as the contact is applied throughout the whold head and face instead of just one part of it.
Again, personally, I just don't see the benefit of using the ones that you have posted pictures of.