Looks like most of the existing replies captured my same use cases!
There have also been a couple of times where my wife and I disagreed about what we did on X day and it’s kind of nice to see who is right 😂
I think I also just like the raw data. I also keep spreadsheets of my utility bills over time, for example, because it’s weirdly fun to look back and see or compare.
One thing I’d really love is a self-hosted all-day heart rate tracker, but have yet to stumble on such a thing.