There are different approaches to website design. There are projects that need a modest and simple aesthetic. The user may not even pay attention to the environment but feel good in there. And then there are projects that need to stand out visually. With design, you can penetrate people's memory, create a special feeling, and say something specific about the product.
The style, of course, is not the sole important element in design. Functionality, simplicity, clarity, consistency - the web designer works with these things to improve the usability of the website.