To me, the whole point of Batty's final scene is his empathy. PKD made a big point of empathy being the defining quality of humans and even the Voight-Kampff test relies on it.

What if Batty saved Deckart to tell him about things he saw? Not for empathy to Deckart, but just to tell a story.

Because, frankly, he may as well try not to kill Deckart, at all. For empathy. Or ask Deckart about how does he do, instead of going into monologue.

I think that's a less interesting story if Batty doesn't develop and has only his self-interest.

I interpret the ending as Batty coming to the end of his life and realising that all life is precious, not just his own. That's why he saves Deckard after toying with him and then goes into his final monologue that taunts Deckard with how much more of a human life that Batty has experienced.

Of course, there's all the Christ symbolism with Batty's "crucified" hand and how he saves Deckard despite him killing all his friends and intending to kill him as well.

> I interpret the ending as Batty coming to the end of his life and realising that all life is precious, not just his own.

The voiceover in the original theatrical version makes this very explicit, in fact.