This doesn't look like a good choice for melee jobs, however mage jobs looking to hit the haste cap for a stun build and such, this beats the alternatives.
Yeah it isn't awesome but 6 haste in neck back waist isn't horrible. I mean it's not like 5+ haste belts are so common and not everyone can wear tiercel
In a set with Tern Stone and Tern Necklace... Waste the neck/back/waist slot for 6% haste... I wouldn't, I'd rather go for the 7% haste belt or the 5% one and use the tiercel necklace and spare the back slot from sucking...