I honestly definitely wouldn't say this is bad for TPing. For some of these jobs, sure, but MNK, THF, NIN all have a sizeable ACC base, and when using Pizza or Sushi, it's generally ramped up to 417+, which would still keep you easily capped on birds. And don't forget, Colibri aren't the only thing in this game that people melee on. Anything Tough or weaker, you'd have easily capped hit rate and that wouldn't change when using this.
Also great for DNC because it already has an Accuracy Bonus trait which more than outweighs the -10 ACC, and also BLU can set Accuracy Bonus. Likewise, it is very good for a RNG that melees (With Merc Kris or Kclub) for TP.
Saying this is bad for TPing is flawed judgment on your part.
Seems to be a common drop off the Tier 3 VNM crab, Krabkatoa. Who can be popped in East Ron, East Ron [S], Jugner, and Jugner [S] using a Blue abyssite key item.
Seriously a decently geared blu should have way more than enough acc in there tp set even with this if they eat even the crappiest sushi out there. In good gear with merits you could still wear this and get away with pizza if you really think that att will do more for you then the str and dex lol
A 10 Level difference (Level 85 enemy) causes a 20% hit rate reduction from Level Correction alone, before the accuracy to evasion check. This partially, or completely, offsets the accuracy increase from using various Sushi and Pizza (depending on which and your base accuracy), so you have to come up with an additional ~25% hit rate in base accuracy against the enemy's evasion to keep (or close in on) the accuracy cap. This is not always easy to do depending on the job and the enemy, even with exceptional gear, traits, base stats, etc.
That being said, against Even Match or below, where Level Correction is greatly in your favor, this helm becomes increasingly user-friendly. Accuracy Buffs (Madrigal/Hunter's Roll/etc) and/or Evasion Down effects (Quickstep/Feint/etc) also help make this feasible.