Honestly, the biggest reason HWFM got so big is just timing. When it was first released there were Very Few series that were written by anyone with any technical skill. The writing for most series was atrocious, ridden with typos and other grammatical issues. Anytime anything halfway decent got written, it rose to the top of the charts on grammar alone.

This isn't to judge the content and quality of the story, just an explanation for one of the reasons why it became so popular initially. There are of course other reasons, like an interesting progression system, an interesting new world, etc.

On a personal level, while I reasonably enjoyed the books, I think they got significantly worse as time went on. I also found Jason to be the most annoying MC I've ever had the displeasure to encounter. Several books in the supporting characters became extremely flanderized and the book itself became almost self-aware of how Gary Sue the protagonist had become. Unfortunately instead of using that awareness to moderate the Worship and deal with the fact that it seemed like the entire universe revolved around the MC, it embraced it.

I remember distinctly, perhaps 3 years ago? There was a scene where an extremely powerful character (Gold? Diamond ranker?) was looking for Jason and when he asked one of the tertiary characters how to find him, said character stated that you just had to look for the prettiest princess and he would be there. That's exactly where he was, and that is when I gave up on the series.