So the Glass Cutter has the unique trait where it has more durability when attacking shadow creatures, some of you may not know this but the Moon Glass Axe has this exact same perk. Some of you might think this innocuous but I well, did the math.
Both items cost moon glass, but the cutter costs 6 while the axe costs 3 this already makes the axe already more efficient in terms of cost, but I see you typing "the axe isn't even a weapon." well it actually has 34 damage, which is the same as a spear, and 200 durability(when attacking shadows) while the glass cutter has 68 damage and 150 durability(also when attacking shadows), and the total damage is
6800 for the moon glass axe
and 10200 for the glass cutter
but as I said before the axe is cheaper than the cutter so with 6 moon glass you could make two axes, bringing the total axe damage to 13600. So you would add 3400 damage for the same cost of moon glass, albeit 34 damage is less than 68 so it would apply slightly slower.
So what this basically means if you only attack shadow creatures with axes instead of cutters you basically cheat the system. This is almost as bad as how they balance turf, eat your heart out, Zark...