I'll dissent and say I don't think it's worth it.
We would write 2 blog posts a month for our client. Did it for 2-3 years. I was skeptical of the impact. We stopped and I removed all the blog posts to see what would happen. Nothing happened. No ranking shift up or down.
For national companies who serve customers all over, blogs make a lot of sense. As you mentioned, you can't capitalize on national traffic. National companies can. But a local blog answering a question about your industry will not have any better chance to show up for a local searcher that is searching a national query than if you weren't local. For questions Google does not prioritize location, unless the question itself is inherently local. Which for local business blog content is almost never the case. A good case being someone Google's "should I get a divorce lawyer". The divorce lawyer down the street from this searcher has no better chance to show up for this query than the divorce lawyer 1,000 miles away. Google does not prioritize location here. They prioritize EAT, which will almost never be in a local business's favor vs national sites that invest heavy in their EAT to answer these type of questions.
Blogs can drive backlinks, which is another reason for a blog. But there's a catch 22 there. Blogs that drive backlinks (really high quality articles) are not scalable for most agencies (you should always be scalable) and usually have to be written by the local business themselves. That rarely happens. And even if it does, they don't know how to do the SEO or the backlink outreach. So, those that can shouldn't (agencies) and those that can't, possibly should (local business owners).
Local blogs also do not drive local traffic in most cases. However, they can help with conversion. They can make you look like the expert, etc.
If you had a really thin site then maybe you could do it for quality. But I've seen sites with 10 pages ranking incredibly well. Google knows local businesses don't really have a lot to say typically, so I don't concern myself with thin content unless it's a YMYL site. And even then, I don't know that I would go with a blog and even if you do, it needs to be done really carefully.
Honestly, every time I see another marketing company writing blogs consistently for their local clients I kind of shake my head. Still waiting for someone to prove me wrong but hasn't happened yet.