Hello there!
I was thinking very prosaically about the extent of the knowledge you’ll learn from the site.
So I began counting every parameter.
Here’s the results for the curious ones out there :
You might be interested in this website https://www.wkstats.com/ which has all kinds of stats including the total number of items available to learn in wanikani. It’s a user-made site by rfindley.
You can learn a lot from WaniKani. I use it for a Kanji review, but to re-enforce readings they use some not-so-often used vocabulary which really helps expand your own Japanese vocabulary if you supplement with other materials (Bunpro, Nihongo-soumatome, Genki, etc.)