Is Subdomains Bad for Seo?

Mueller concluded that subdomains generally don't hurt site rankings. He argued that Google's algorithms are good at crawling subdomains and subdirectories equally well and making sense of what you are trying to do.

Why you shouldn't use subdomains?

Since subdomains are crawled separately, having the content and links on a subdomain – separate from the main site – means their results and authority are also divided. Google says that you won't be punished for listing it separately, but it won't help you either.

Are subdomains or subdirectories better for SEO?

According to some SEO experts, another benefit is that subdomains can help build niche authority. For instance, you might want your blog to be considered a separate entity from your product or service. ... If you don't have a compelling reason to use subdomains, then subdirectories work just fine.