Read the original article here: Why I Love Ugly Interfaces
Most problems are multi-objective. Optimizing for one goal can undermine another. Beauty and ease of use are important goals, but are often at odds with featureful software. It's ok to have a complex and thus ugly UI if the requirements are complex. This is not a free pass to ignore UX, just a reminder that everything should be made as simple as possible, but no simpler.
Also, what makes a UI easy for a beginner may hurt the efficacy of the advanced user.