@thedisasterautist It started some years ago when the market was much more competitive, & sellers could pick & choose who they sold their home to. Buyers started writing letters of appeal, basically - a "here's why you should pick me to buy your house" letter.
@thedisasterautist It seems to have become more of a thing now that there was a precedent established for it. I was advised to write one by my agent, to gain sympathy from the buyer as we start in on the whole negotiating process.