I have two relatives-by-marriage who do this. They are parents and child, so it is the same news twice, from slightly different perspectives. The last time I responded to one, I received no further reply, so I simply figure they do this for themselves.
“... they do this for themselves”.
You hit on my sentiment about these type of cards exactly. I always thought to myself, “Who are you trying to convince? Us or yourself?” To be fair, my husband has a friend that sends out a parody of these type cards and you read it with tears rolling down your face. He’ll discuss the septic system backing up, the operation of his dog getting neutered, or updating us all on his enlarged prostate. It is the funniest card, written with such humor that you end up saying, “gee, our year is so much better”. (which is his point and gift, I guess).