I would classify that act of editing as "completing the remaining 10% of the work." Somebody has to do it, whether you're doing it from the writing side as in your example, or making the reader do it from their side, as in my grandparent comment's example. But it's usually the last 10% of anything that's the hardest, so if someone abdicates that to a machine and signs their name to it (claiming they said it, and taking responsibility for it) they're kind of an asshole, in both the schlemiel and the schlemozel senses of the word.
I could extrapolate in my extremely judgmental way that the person who does that probably has a grandiose sense of how valuable their own time is, first of all, and secondly an impractical and sheepishly obedient devotion to big weddings with guest-lists longer than the list of people they actually give a shit about. Increase efficiency in your life further upstream, by inviting fewer people! (Yeah right, might as well tell them to save money by shopping less and taking fewer trips. Like that would ever work!)
But I digress, and anyway don't take any of that too seriously, as 20 years ago I was saying the same kinds of things about mobile phones... like "Who do you think you are, a surgeon, with that phone?" Notice it's inherently a scarcity-based viewpoint, based on the previous however-many years when mobile phones really were the province only of doctors and the like. Now they're everywhere... So, bottom line, I think the thank-you notes are a lousy use of the tech, but just like the trivial discretionary conversations I hear people having on their mobile phones now that they're ubiquitous, this WILL be used for thank-you notes!