Indent for code blocks is a non-starter. Can't paste easily, very annoying to type in a web form. Triple backticks is the right thing.

Triple backticks also let you specify the syntax very conveniently.

Add to that using -> to designate a link with a numbered URL for the actual href (numbered hrefs are already in Markdown), and also needing to indent list items... this is a solution in search of a problem.