Compacting HTML code, including any inline JavaScript and CSS contained in it, can save many bytes of data and speed up downloading, parsing, and execution time.
Minifying HTML has the same benefits as those for minifying CSS and JS: reducing network latency, enhancing compression, and faster browser loading and execution. Moreover, HTML frequently contains inline JS code (in <script> tags) and inline CSS (in <style> tags), so it is useful to minify these as well.