I'd hate to get that by email every day when there are much more efficient ways of doing it, like automating a scheduled task on my PC... like I already do now, but that's just me.
The problem with deltas is that to restore the database you have to rebuild it incrementally rather than a single restore motion, and I'd personally hesitate to build such an option for users that will inevitably get it wrong, which is why I abandoned development of so many mods over the time I was modding, knowing the support issues, so ultimately I'd suggest SMF not take that course as a standard feature personally.
It's not impossible to chunk, of course, just the restoration is sufficiently complicated it would confuse most users here, I think, knowing the number of times I got fed up with people who didn't even read what was put in front of them multiple times in large red letters. That said, it gives me an idea for the other thing I'm working on...