It's quite hard to explain the problem with nibs, particularly because in the short term they are fine. It is after a couple of years that the issues start to appear. Take this normal guitar neck Everything seems fine until the season changes and the neck shrinks. On a "normal" guitar, this is when you feel a little fret protrusion. You can either ignore it or get the ends dressed. On a guitar with nibs, something much nastier happens. The fret has no give, and the nibs are pushed outwards. They may or may not tilt, depending on how they were fitted, but make no mistake, they will move. The forces at work are huge. The season changes again, and the neck returns to its original size. But there is nothing that can make the nibs go back with it, and this is the final situation, well known to all nib-haters. Not yet experienced by nib lovers. And there we have the string traps, just waiting for you to fall in.