Hm, a hearing aid store in the next big town over from me has taken that approach. For the past several years, somebody has been taking the time to handwrite little notes and hand address envelopes. The first time I got one, I was very curious to open it, for the same reason you were. Who sends handwritten letters anymore?

But when I opened it and saw it was just a sales pitch ... ugh.

I've received two or three more in the years since I opened the first one. Now I don't open them anymore. I guess I take mild offense at the idea that somebody's trying to trick me into believing I've received a personal letter.

So I'm not filled with good will toward that hearing aid store. I expect people evangelized by something that masquerades as a personal letter would feel similarly.