Websites are very important imho because when done well they add a lot of legitimacy to your online presence. As others have said, it's important to have you own domain name with WhoIs protection (very cheap these days) and the website should have original content on it through a blog or collection of articles/stories.
This all comes with a caveat...do it properly! Layout, header images, font choice, colouring, all these thing should add together to create a pleasant and easy experience for your readers. Avoid the temptation to plaster your site with affiliate ads, they are incredibly off-putting. Take pride in your site and people will respect you and be interested in your work, throw one together without care and they will walk away.
one additional reason to become a blogger is because it lets you promote your book indirectly through relevant topics. If you check out my website (Future Conscience, link below - Wordpress site using Headway paid theme for custom layout) you can see the post on ocean cities which is a recent one I wrote to do just this. This post has had well over 500 unique readers at this stage, and could be posted on places such as Reddit legitimately. This approach lets you overcome the dreaded 'buy my book!' groundhog day on social media...which is necessary in a way, but much better to have some variety!
In my opinion, it's more important to build relationships then find one-off sales. A good blog will let you do exactly that very effectively.
Good luck!