The first time I used this script, I felt annoyed, because I don’t want to be reminded which specific item that will test me on WaniKani. But, when I learned that I could turn it off from the setting, not anymore. Although I almost never use my Chrome browser to review items because I can’t use text completion on my touchbar as easily as when I use Safari on my Mac, I like to see the graphs and my WK dashboard on Chrome. I also use my iPad, iPhone and/or other Android gadgets to review, so I don’t rely on this script that much while commuting.
For me, it’s okay to be reminded about kanji/vocabs that I’ve learned, but not on WaniKani site, like on NHK TV, WakuWaku Japan TV, Apple Music J-Pop Lyrics, NHK Web Easy, tweets by native japanese, YouTube videos by native Japanese. If only I had much more budgets, I would buy and read Japanese Graded Readers one at a time.
But it’s just my personal preference, it may work differently on each individual. I’m not the type of being overwhelmed by “Oh, so many unlocked items, things to learn”. I’m the type of feeling constricted by too many apprentice items (It’s okay for me to have more than a hundred apprentice items, but I like to keep it low again in about a week). Maybe if you feel overwhelmed by too much information to absorb, it’s good to turn it off, and focus on WK & genki.