I've recently learned about holding the priority after playing a spell or ability.

I understand this can be used for beneficial effects affecting your own spells, for instance copying your own instant/sorcery with [Twincast](http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=191322) or [Reverberate](http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=290289).

But since the stack resolves it's content 1 by 1, I don't see how playing two spells back to back without passing priority would differ from playing one, let it resolve, then play another.

Apart from spell copying/redirecting/etc... effects, what would holding the priority allow a player to achieve ?