There's nothing stopping you from doing that with an LLM. I get more insights refining a draft through prompts than I ever did writing because there's more of it. The end stage of that process rarely sees the light of day because the artifact wasn't the point.
For writing as thinking with trouble starting from scratch, LLMs are the most important technology to emerge in my lifetime. Microblogging filled that gap in a way, but it had too many downsides.
>> you will not have that delightful experience of encountering something unexpected along the way to filling it.
> There's nothing stopping you from doing that with an LLM.
There may be, though. The LLM's initial output may anchor your thinking in insidious ways that may not be obvious at all especially since you're feeling productive. I bet the lack of confidence around starting would also increase over time every time you use an LLM to get over the hump.