I crafted a legendary wooden bow (because I wanted to stay with bow instead of crossbow, so there was a large gap until composite bow). I crafted a legendary pistol because I don't like the magnum at all. I currently still use the (silenced) pistol in parallel to the MP5 I crafted recently.
There is an argument even for crafting the legendary knife, because a quality1 machete uses double the stamina, but only has double damage on normal attacks not power attacks, and you mostly do power attacks with knifes and machetes.
I would craft legendary pusher turrets when playing INT, as they are very very useful with specific horde bases, more than the shooty turrets.
Okay, but that's it. Apart from INT and AGI players the only reason to craft legendary weapons is to craft them with an additional mod slot NOW instead of waiting for more magazines until the next step is available. Makes sense if you have enough legendary parts.