With ToAU, this ring is not as effective in 72-75 exp/merit pts (unless you're not pulling, but you almost always do) because a good chunk of the mobs you'll be pulling runs faster than you.
If the party decides to merit in Caederva, you'll have to worry about Jnun auto-aggro you from far away... You may think you want Jnuns to auto-aggro for easy pulls, but if an imp gets around to AoE silence when another mob is pulled into the melee's spot, you're as good as dead. Echo drops are consumable and they rarely last for BRD due to our nature needing to be close to melees to cast songs.
For mamool training grounds (besides the mamools), scoffins, puks, and mamool stabler's raptors will outrun you. If the exp ground gets infested with other parties, you may be forced to do long pulls, which is very risky due to double attacks. If your party gets the place all to yourselves, then this ring is worth the bang for its buck.
Mt. Zaohym (however you spell it) is probably the safest place to use this ring since the trolls don't run faster than you.
Greater Colibris @ Bhaflau via Nzyul Isle is very questionable because there will be times where an accidental linkage occur. Can't use Horde Lullaby or you risk the high possibility in sleeping your whole party. You'll end up needing to sleep the colibri that doesn't have elegy while try to rotate shadows to avoid getting beaten to death by the colibri that has elegy, all the while hoping your party finishes the mob they are working on. I rarely get beaten up here, but at times my HP hits orange because of the scenario stated above, and that is with me starting with full HP. You can run horde lullaby and then run out of range so the colibri puts you to sleep from faraway to prevent the party from going zzzz. But if there's competition in that area, a second asleep is a second late in pulling the next mob whose name will turn purple in a heartbeat. You don't want the healer to put the colibri to sleep because they can be put to sleep when the bird wakes up. risky deal to keep health in yellow.
For HNM/gods/etc... its too risky to keep your health yellow knowing the fact that a random AoE can mean instant death.