Am I? It lets you gather many disparate forms of information from a variety of sources so they can be organized, annotated, and searched in a unified manner. It provides the same capabilities across multiple different platforms. Users perform many different tasks in Evernote.
I believe versatility is one of Evernote's goals. I believe another is efficiency. I think Markdown addresses both of those goals, and would be an extremely effective input and formatting method for a certain class of users.