Good questions have a habit of turning up at inconvenient times. A sentence in a novel stays with you long after you’ve forgotten the plot. A tool that saves ten minutes makes you wonder why the task took so long in the first place.
Writing those questions down makes it easier to come back to them. Sometimes an idea gets clearer when you try to explain it. Sometimes it gets stranger, and that’s a good reason to keep going.
That’s enough to begin a blog. A question worth keeping can carry a piece on its own.