On a phone, a manga page and a casino screen compete for the same scarce space:...

https://wiki-room.win/index.php/Why_Does_Seeing_Multiple_Panels_at_Once_Change_the_Reading_Experience%3F

On a phone, a manga page and a casino screen compete for the same scarce space: your attention. Strong focal points guide the eye, readable controls prevent squinting, and smart contrast keeps details clear without clutter