What is the practical difference between <em> and <cite> tags in html?

Answer 1

The <em> tag is a phrase tag. It renders as emphasized text

<cite> tag defines the title of a work (e.g. a book, asong, a movie, etc.)

Answer 2

They can be targeted differently by css formatting.

Also a lot of HTML tags are semantic, so although there may be no difference visually, a browser or search engine may treat it different (e.g. tags to denote acronyms). A browser for those with visual impairment may also read this portion differently or indicate it's a quote, rather than emphasized text