According to the living style guide (https://tools.wmflabs.org/styleguide/desktop/section-2.html) the current styling for "quiet buttons" is dark grey bold text with a blue hover state, and no outline, underline, or other indication it is clickable (or even what area it encompasses). Since we don't have hover states on mobile, there is no way to tell that a quiet button is actually a button (rather then just grey text). And you can't always assume this just from the text being a verb. For example, in the mobile login CTA we have "Help improve this page", "Log in", "Sign up", and "Edit without logging in". "Help improve this page" isn't clickable even though it's a verb in grey text.