I agree with AimlessWanderer completely. I struggle to keep a diary or journal for all the same reasons. I have tried and failed many times. I don't think I want to read my own entries and nobody else would be interested. So what's the point?
For me it is a process discipline, not an outcome focus. The value is the daily time to think, reflect and journal. There is no expectation of me or anyone else going back and reading/reviewing.
Agree that needing the end product to be useful for something could be be a barrier to getting started or sustaining a journal practice. If I put that kind of pressure on myself, I would toss it all in the trash and walk away.