possibly the website because it has so much more elements to load now vs the previous version which only had spotlight, popular, trending, staff picks, and the app exclusive stuff before the buttons at the very bottom for the store/creators/fresh/etc.
Now there's a bunch of banners leading to comics, a ton of rows that are extremely specific (top 10 comics/books, romance comics, etc.) and so on. I can really see it slowing down for others who's computers aren't as hi-tech or people with internet running on the slow side because its a lot to load at first glance. that's my guess anyway.
again, having it match the aesthetics of the app is understandable, but desktop websites function & read entirely different since you're not limited to a tiny screen. its the first iteration of the design and thankfully it looks like they're willing to change things around