If you need to send out 200 personalized letters to sales leads but haven’t got the time to handwrite them yourself — or if your handwriting is, like mine, grotesque — then Maillift will generate them for you, using teams of genuinely carbon-based people. That's horrible! I don't mind getting a printed letter but if I got a handwritten letter that I later found out was faked I would never, ever do business with that…
What about when you get an email from a website you just signed up for that opens with "Hi, Anigbrowl! I saw that you signed up for my site..." and is "signed" by the CEO. If you found out that was an automated email and that the CEO didn't really type it up personally, would you be equally upset?
What I'm saying is that the more personal-seeming it appears, the more attention the reader is likely to pay. An actual handwritten letter presents as a highly personal communication. Even where it's justa courtesy note, it says that the other person values your business enough to take time to literally put pen to paper. For example, a few times I've bough a used book via Amazon and it arrived with a hand-written note of the 'thank you, hope you enjoy it' variety. It may be done by some junior employee, but any firm that does that goes straight into my 'preferred sellers' list because it's a rare flourish of personal courtesy in a world where most things are mass produced and commoditized.