The accessory could be useful in the beginning of the game, but it is easily replaced with another accessory as the player can easily enough set up an automatic Libra effect with the gambit system with Self:Libra; only one party member needs to have Libra for the player to see information on enemies and for traps to be visible.
In the original PlayStation 2 versions, the Bangle can be bought for 500 gil in Dalmasca Estersand, Giza Plains - The Dry, Dalmasca Westersand, and the Barheim Passage (before obtaining the Treaty-Blade). It is also found as a treasure in Paramina Rift's Frozen Brook, in the middle of the area when the treasure is not gil. Ashe also joins the party with a Bangle equipped.
In the updated Zodiac versions, the Bangle can be bought for 500 gil from Giza Plains - The Dry, Barheim Passage, Dreadnought Leviathan, Dalmasca Westersand (after Ondore's Estate), Mosphoran Highwaste (after defeating Judge Bergan), and from Dyce and the "secret shop" in Necrohol of Nabudis. However, as the party gets one Bangle for free from Ashe, who joins with a Bangle equipped to her, there is no need to purchase one as one is enough for any situation.
Bangle is also found as a treasure in the Dalmasca Estersand's Banks of the Nebra and Broken Sands, the Paramina Rift's Frozen Brook, the Tchita Uplands's Sundered Earth, the Pharos - First Ascent's Wellspring Ravel - 3rd Flight, and in the Trial Mode Stage 8 & 30 with the Diamond Armlet equipped.
The Pilika's Diary sidequest now also has Bangle as a reward: the player gets it if they tell Pilika they read her diary.