I'm a huge fan of grimlocks but only really for attaching things to a plate carrier, so not really typical bushcraft use. I used four on the back to attach a camelback and one on the left shoulder to attach a rifle sling. Their advantage is that they release under a load of 50 or so kilos so you don't get hung up on gear if it catches when descending. They are handy for clipping gloves quickly too.
im sure they do have there uses. But I bought them thinking they would be handy but I had no real plan for them they just looked cool and I still don't really have a good use for them. So in my case they were a little bit wasteful. I my intension for the thread was to list kit you wasted money on for any reason and not just a list of rubbish kit. ie spending hundreds on a high spec sleeping bag only to find it is too warm to sleep in comfortably. the thing with bush craft type kit is a lot is personal preference and experiment trying to find out what is best for you. what works for one person is not always the best choice for someone else