Superblog can only be hosted on a sub-domain. Meaning, you can have your blog address like this blog.yoursite.com and not yoursite.com/blog. This is due to the way superblog's technology is built and for you to make use of complete benefits of superblog's CDN, servers and technology. If you host superblog on your own website's path, it means superblog will be limited by your server's capabilities. It's quite counter-intuitive.
What is the SEO impact of using a sub-domain for a blog?
Half baked SEO professionals just say to go for subdirectory because google considers sub-domain as a different site. Yes, google does that but for blogs subdomains are treated as a part of the parent site.
This is what Google's John Mueller says:
In this video, John states that
Google web search is fine with either subdomains or subdirectories.
We do have to learn how to crawl[subdomains] separately, but for the most part, that's just a formality for the first few days.
Some of the biggest companies use sub-domain for their blogs
And all of them do heavy content marketing!
Not convinced enough? No problem.