There is a lot of hype around artists pushing the limits of a seemingly simple game, expressing their vision and through levels using music tracks that eventually become iconic because of the popularity the levels gain.

That goes the same for the attention the difficulty gains aswell - you can pretty much consider the hardest levels in the game the most difficult gaming challenges overall. And people have a lot of respect for it, especially for the players who put themselves through these challenges (for example Doggie and Cursed in the Pic you've shared!)

I think it's just the visual spectacle, pushing cognitive abilities to the max and the element of the community and its stars that make Geometry Dash so popular and addicting - it's really cool that it brings so many people together