As they say: "Give a man a fish and you feed him for a day; teach a man to fish and you feed him for a lifetime."
One of my favorite sentences... But in this very case making delta @ home would make little sense, because the time you spare in the update process would be nullified by the time employed to prepare the deltas. From a standard home user perspective the whole delta thing would make sense (a lot of sense for 1507/1607) if a trusted user would prepare and share them. Obviously a sysadmin that has 200 machines to maintain would spare a lot of time, even making the deltas by himself, given in that case the time employed to prepare the delta would be a one time task, and the spared time would happen 200 times.
I know it a little different: "Give a man a fire and he's warm for a day. Set a man on fire and he's warm for the rest of his life."
That's the joke. Yes, he'd be soon dead, but until then, also very warm. It was never mentioned how long "the rest of his life" would be. Having to explain jokes is so meh. And yes, it's crude humor, but that joke's not from me, I swear.