There are so many benefits around having a personal blog that I'm surprised about reading all these negative comments.
I started blogging about tech and security when I was 13/14 years old in my native language. Then, when I felt more mature, I switched to a new blog where English was the main language. I started improving my language skills, getting some donation from kind strangers for my blog posts and using it as a self-branding forever running-side project.
Now, 20 years later I still have my personal blog and I still write about tech, but only recently I created some "personal related" tabs, like the "/now" page, enriching it every month or having a more personal about page. Why? Because I like going to a blog a see that behind that address there is a real person with emotions and dreams, it's like entering in their home and have a look around.
1. Improve your language skills
2. Self-branding
3. Memorize better topics you care about
4. Share what you learned with others
About LLM, I don't care if they scrape my blog, I use LLMs every day, and if some stuff I write helps to enrich an LLM with a positive impact I would be more than happy to let it happens, the more we write, the less fake-news and low-quality content would ingest and used.