Quote Originally Posted by Aidoru View Post
Wiki says

バーストダメージアップ　Lv1毎に+1.5% (バースト倍率に加算)　例：バフLv100 SSR神姫のバースト倍率が5倍(500%)か 6.5倍(650%)に

Google translates to
Burst Damage Increment + 1.5% per Lv 1 (Add to Burst Magnification) Example: SSF Shinki burst magnification increases from 5 times (500%) to 6.5 times (650%) with buff Lv 100
(Not sure why google translates SSR to SSF but the original Japanese text says SSR)
What this means is that for an SSR and a Burst buff at 100 stacks, Burst damage increases by 25%. But Burst damage is only a fraction of your sustained damage, usually less than half, so divide by 2.5. So the Burst buff increases your team's sustained DPS by about 10%. Meanwhile double attack/triple attack not only increase your sustained DPS, they also allow you to Burst more often, so I can definitely see how those would be preferable.