There are several benefits of using Semantic HTML:

1. It brings about structure and clarity in the code.

2. Well-constructed and clearly interpretable markup helps with Search Engine Optimization (SEO). Search Engines are able to parse and find headings, paragraph texts and key words from a document much more easily if semantic HTML is used. So, semantic HTML increases SEO scores of a HTML document.

3. Semantically strutured HTML document favors accessiblity of a website using screenreaders. The site can be navigated better with semantic HTML by visually impaired people.

4. Semantic HTML is developer friendly, as it helps with both writing and reading the code.

5. It helps avoid writing unnecessary markup that may increase the size of an HTML document.

References

1. Semantics in HTML
2. HTML: A good basis for accessibility