[marcosdumay]

About #7, the article is not advocating making things not look like a button¹, it's advocating making secondary buttons lighter.

1 - In fact, the buttons there don't look like buttons. But that's because it uses a normal design, and nobody creates buttons that look like buttons anymore. Could we please standardize the "button look" with a small, fuzzy outset?

[Silhouette]

Well, the examples of tertiary buttons under #7 are plain text or plain text with an underline, and the article text specifically mentions styling tertiary actions like links as being "usually the best approach". It pretty much does exactly advocate making things not look like a button.