1/ what do you feel like you've learned or gained from this?
2/ do you ever go back and study what you wrote or is it more about giving your thoughts clarity today?
1/ For me it's similar to meditation in terms of the appeal. It's a way to slow down and think, not necessarily for measurable gain but to be a bit more present in the flow of things. I've learned a lot about myself as I do a lot of introspection when writing.
2/ Yes, a major feature I'd like to build is a retrospective flow as I've developed a pretty nice system for going back and pulling out "nuggets" from past entries. Seeing your own thoughts after some time, as a stranger is a really useful tool to understand how your mind works.
Not OP, but have been journaling for the past 7 years with some pauses in between.
The greatest tools for me are:
1. When I'm feeling as if I'm stuck I go back sometime (like a week) and confirm that I've indeed progressed.
2. My recollection of events is better just because I'm logging them. If I really want to confirm something I can go back and check. This is specially helpful in day to day issue resolution with my wife, which has been an important topic for us.
3. Sometimes I go back a year or more to just have some memories. It helps me to feel human because I had big troubles with long term memory.
I've been journaling for 20 years and often I open old files to talk to the younger me. It's remarkable how you change over the years, a feeling that, AFAIK, any other medium achieves (maybe video/audio recordings, but text is way simpler to register, storage, and retrieve).
It's one of the things I'm most grateful of doing for so long.
I'm not the OP, but for #2, it's almost all about the latter. Occasionally I go check on random or specific days.
What have I learned or gained? It definitely helps ground me in the flow of time. It's so easy to lose weeks or months or years if you're never reflecting. Journaling helps me be more aware day to day.