Web hosting for a blog is necessary or not depending on your blog and future plans.
If you want to create a blog for fun and do not want to spend money on a blog, then web hosting is not necessary.
Because, in such a situation, you can host your blog on Blogger or on WordPress for free, without buying hosting. But, yes, on these free options, you have to follow their rules.
If you want to create a blog for passive income and want to expand more in future, then web hosting is definitely necessary for a blog.
Because, after buying web hosting – you can avoid free hosting limitations, be able to set up a blog with desired options (platform, themes, plugins etc.,), create a professional impression on visitors’ minds and more.
So, that’s the answer.
Hope, answer is simple and easy to understand for all.