Designer: The web design muset be beautiful, clean and follow modern trends.
Me: Actualy no, design should be just functional part of website. There is no need to be beautiful, clean and has nothing to do with modern graphic trends. Sad truth is almost nobody, besides css galleries, cares.
Designer:

Deisgners are mostly fucktards who dick around in Photoshop and don't know shit about actual UI design, accessibility or even fucking usability.

Their latest "trends" as evidenced by freakshows like aaawkwards and drivvle serve at best as bad examples how not to do it.

They deserve to be anally electrocuted with a high voltage cactus!

Designer is right though. Marketing is selling a backend functionality, but frontend is the face of it (and in a way - a face of the company). If that face is not attractive or even repelling or at least attractive than your competitor's face you are most likely going to lose cusromers to your competitors.

If we're talking about an internal tool's FE then I agree with you - it only has to be functional and work correctly