If you use superglue on leather it hardens and becomes one with the wood. You can apply graphite so the string would feel just like in a regular bridge slot. It's not as good as wooden insert but it's almost just as good, to me, sound wise, and it's not permanent.
I wouldn't call ca/ebony dust repair cheesy. Not sure if it's great for the bridge but it certainly is ok to do if someone grooved the slots too deep and you need quick repair. Anyways, these methods are not something permanent, it's just a quick fix, if you want something better you just make a new bridge/nut, but for an emergency repair to me it's ok
I wouldn't call ca/ebony dust repair cheesy. Not sure if it's great for the bridge but it certainly is ok to do if someone grooved the slots too deep and you need quick repair. Anyways, these methods are not something permanent, it's just a quick fix, if you want something better you just make a new bridge/nut, but for an emergency repair to me it's ok