In that it distills the game mechanic of “make number go up” into a simplistic form. It just lakes the clicking.
PS, whenever I relapse and play too much World of Warcraft, I play some Cookie Clicker as a cleanse to remind myself of the fundamental pointlessness of the whole endeavor. Great game.
I think it is one of the few games that "changed my life" in the sense that by getting addicted to it for a few days, it made me see Cookie Clicker in every platform that tries to waste my time.
I remember when I first heard about it and I naively thought that such a simple game was silly and in now way could not be addictive, but I let myself play it for a while and it really changed the way I see games.
This is a great insight, you see it in a lot of mobile games and "live services" / MMOs especially, a big focus on "numbers go up" with relatively minimal effort or skill involved (or only the perception thereof).
In a similar vein, "stamina" in mobile games that limit how much you can do, which on the one side makes the game not "feel" like it takes much time, but which on the other encourages you to open it up a few times a day, and / or buy the "restore stamina" purchase.
"Dailies" / "weeklies", things you should do every day / week to stay up to date.
"time limited events", miss it and you'll never get the chance again.
https://orteil.dashnet.org/cookieclicker/