I've had a personal blog for 20 years (at
https://b3n.org/).
1. I have met a lot of people who reached out to me by email; sometimes it's fun to find other people with similar interests, it's resulted in many good discussions (even with people with differing viewpoints).
2. I have not landed any jobs from it (but I have been offered a lot of contract work--I have turned every opportunity down because I don't want to take time from my family).
3. Writing helps clarify thought. I often correct my own thinking through the process of writing. I'm not a great writer, but I'm a better writer because of blogging.
4. I also enjoy it, I wouldn't do it otherwise. I don't do it for others, I don't try to optimize for SEO or pick popular topics or grow a large audience. If I see another blog has written a similar post I usually don't see the need to write my own. I write what (a) what I enjoy writing or (b) what must be written even if it isn't popular or (c) what I think will be useful to others.
5. I'm often terrified at how bad my early posts were. At least I can see the growth!
6. Even though it's not the most efficient way to host, there is something special about hosting a blog from a server in your own garage.
7. I have more control on a blog (both in terms of freedom and expression) than I would writing on social media.
8. It's a way to leverage your knowledge. If I figure something out, I'll post it. It might cost me a few hours to write, but then for the next few years thousands of other people may benefit saving hours of time, research or money.