It's hard to share projects before they're finished because they feel raw and you may not be proud of them yet. For programming projects, I often feel like there aren't enough features, it looks ugly, or I haven't handled edge cases yet. And for writing projects, my ideas might feel muddled.
The truth is that many people have ideas, but very few of them are worked on to completion. It's easy to get 80% done, but it takes discipline to actually finish.
Once you get to v0.1, it's easier to get concrete feedback on how to improve and to start making adjustments. Mentally, it takes less energy to edit a blog post (even if it's bad) than to start from scratch. Instead of polishing something to perfection, finish the first version as quickly as possible, so you can start iterating.