Interesting . . . in the BAFs I've done since this game has come back (I'd count about 50+) I've never noticed that called out as a tactic for any scrapper, or anyone. It's usually just pull Siege and Nightstar at appropriate times and the entire League goes to town. Usually there are enough folks beating on them that if one of the main targets get sequestered by Siege/Nightstar, they can dip out and the beatdown can still continue. For the BAF the main thing usually is just watching out that both die nearly at the same time in that last stage. But that just pure full on League damage. The adds that come with both over specific time periods we just ignore or they get mauled by splash damage. . . . and that's probably because enough of the League members by now aren't new incarnates that makes that possible.
But I can see how it can be used in other situations.