This is an amazing new feature in WatchOS 27, only with the very latest Ultra 4 or Series 12 which have the necessary onboard processing power. It’s so compelling that I’ve immediately placed a pre-order for a Series 12.
The Siri Recap feature summarises everything the watch hears during the day (with no audio recording), with an on/off schedule if desired. This looks to be a really useful source for Journaling.