Outside of that plantera cheese fetid bangheds are extremely impractical. Not even sure if they can do that after their nerf.
If combined with the Titan Glove or any upgrade for knockback (something you should have), Fetid Baghnakhs can be used quite well to mow through enemies without having to pay so much attention to spacing, because you deal the perfect amount of knockback to keep almost anything either in the blades or just outside of them. Many enemies will get torn apart by running in their direction while swinging the claws, and although you would never even think about using it for bosses in any situation (even Plantera) it definitely still holds its own against common enemies.
That might just be a close ranged shredder bias kicking in however, because I hold the same opinion for Psycho Knife, and for Starlight even though it was actually buffed because people considered it too weak.
From my expeirence with the bladetounge its pretty underwhelming, I've heard people say its good for destroyer but a million things are good against destroyer.
Yeah, I’d never use it on Destroyer. Sounds like a great way to get one shot by his 400 damage head, and there’s no way to dodge the lasers. Besides, Deatroyer is Drippler Crippler’s job.
However, its by far the most valuable melee weapon for invasions up until Death Sickle, since invasions are one of the only good times to use a broadsword and you smear the crowd with a jet of piercing ichor with every hit.
I haven't used chain guilitenes after they got buffed, so they may be better than I remember.
Buff was pretty significant. It pulls more DPS than most other melee weapons of its tier. Its range and knockback make it pretty hard to use against many enemies, but it reaches much farther if you’re moving in the opposite direction you aim, which makes it great for chasers like the Twins, Duke Fishron if you choose to do him early, or Prime during his spin attack.
I’ll keep Flying Knife in mind as an option for the future, it does seem more popular than I give it credit for, but I absolutely don’t see myself using it over Shadowflame Knives for the mechs.