There is no one definitive answer to this question. In general, hosting services can be helpful for WordPress blogs if you need to:
Enable automatic updates of your blog software.
Have more control over the appearance of your blog.
Have access to technical support.
However, depending on your needs, you may not need a hosting service at all. If you’re comfortable managing your own blog software updates and website hosting, you can typically do so without additional assistance. Additionally, many WordPress bloggers use self-hosted WordPress blogs without any hosting services at all. This allows them complete control over their blog software and website design, which can be advantageous in some circumstances.
Ultimately, it depends on your specific needs and preferences as a blogger which type of hosting service is best for you. In general, though, hosting services can be helpful for WordPress blogs if you need them.