My dearly beloved first husband has DONE this for ever: I used to feel inadequate reading his annual report, comparing his months away in exotic places to my Motorhome trips.
Happy with my lot now.
I can't DENY that most of these "round robin" letters do seem to be a bit like showing off about all their achievements or listing all the amazing things they've done during the year. That's why I prefer to write individual letters, personal to the recipients.