Some UA provide very high (empirically at least 90%, but less than 100%, suspect 99%, same as faleria or conquerors buff) evasion to the whole union while they are ready to go. It might be benefitical to fail triggers on purpose if said UA is below enemy in queue to dodge its attack before launching urs. Arts that DO benefit from this: all RWAs, both omnistrikes, phantom pain. Arts that DO NOT: summons (moot, since they resolve before anything else), conjurations, ex-machina, lughs revenge, thousand flowers, beowolf. To test: both assisted snowpetals, UAs on other Seven.