Carbine hooks are excellent quick fasteners, but choosing the right one is tricky. Sometimes the opening is too small, sometimes pin moves too close to carbine bottom or if it fits your line, it does not fit port rigging ring size. For controlled choice you have to print out picture, and measure it compared to fixing points. But who has time to do it! So I started to compare carbine with other types of hooks and appears it is not as good many matters:

Maybe it is not honest comparison, but keyless shackle is as handy to use but is 4x lighter at same comparable length and opening size. Of course, keyless shackle will never replace carbine hook where rapid one hand fixing is needed. Just to consider, how much heavy steel you need when choosing one.