In the deleted scene, Deckard visits Holden in the hospital while he’s recovering from the gunshot wounds. Holden here has seen better days; he’s happy to be alive, but disappointed in himself for letting a replicant get the best of him. His main purpose in the scene, however, is to warn Deckard about what’s ahead of him. “It’s a wipeout. They’re almost us, Deck. They’re a disease,” he says.
It’s an interesting exchange that establishes how dangerous Deckard’s new assignment is about to be, but also sets up one of the central thematic questions in the movie: Should the replicants be wiped out like a disease? The fact that they’ve become so indistinguishable from humans is scary to all the human characters, but is that the right reaction? As the movie goes on and Deckard’s given reasons to doubt his own status as a human, we’re left to wonder if maybe these replicants deserve to live just as long as a regular human would be allowed.
The other benefit of the scene is that it would let Holden leave a bit more of an impression on the audience before he leaves the movie for good. The deleted scene leaves him in a deeply sympathetic position, with his health seriously harmed and him quickly developing what seems like a dangerous morphine addiction. It serves as another reminder that Deckard’s life is likely unsustainable. Deckard needs to change his line of work, or at the very least his outlook on life, if he ever wants to be happy.