I'm assuming the website was made by one person who wanted to earn money from doing scanlation, in this case, the problem isn't really with the design. He took the most basic template ever which definitely wasn't designed by a 3yo and added some crappy banners.
The problem is actually with the reader, which is dogshit. The images aren't properly proportioned. He took the pages and pasted them as is. And it's not readable at all unless you manually zoom out.