It’s not a matter of coolness, but resistance to abuse. Unrestricted HTML is not an option for comments, because it can contain Javascript, or formatting that breaks the entire page. A restricted subset of HTML could be allowed, but it would be about as complicated to support as Markdown is. Support for Markdown came free with the Reddit code base, but adding restricted HTML as an option would be a nontrivial project.
It’s not a matter of coolness, but resistance to abuse. Unrestricted HTML is not an option for comments, because it can contain Javascript, or formatting that breaks the entire page. A restricted subset of HTML could be allowed, but it would be about as complicated to support as Markdown is. Support for Markdown came free with the Reddit code base, but adding restricted HTML as an option would be a nontrivial project.