Overall help in PvP/Arena? Not really.
If you play a class that can cast dispellable buffs (Fort, MotW, Kings/Might, ect) that trinket can proc off those casts, making you suffer the 45s ICD. It also doesn't allow for the on-demand damage players need it for with their cooldowns. So while it would technically be a DPS increase if this were like PvE, not being able to control when you have the damage (it could proc off a dot while you're in a full poly for example) makes them still less wanted than the on-uses for most classes.