Why Does Layout Shift Lose the Sale?

Guillermo Rauch says layout shift loses the sale. He gives business people this case: a shopper is about to press buy, an engineer's mistake shifts the page down, and the shopper clicks an ad, leaves the site, or goes back. The sale is gone. A product that janks and jitters on load does not feel good, and conversions fall when the layout work is sloppy. The browser has already done the math and is ready to paint, then has to calculate the page again. He compares that waste to code that makes an app load five times, burning time, compute, and energy.

Layout shift also erodes trust. It feels unreliable, the way a shifty person does not feel trustworthy. People should still be free to break a rule instead of following dogma. The web experience he wants is a highly honed video game, where sprites appear on a stable horizon and do not jump around.

The picture he gives is a Japanese art of painting a dragon in one stroke. The brush is loaded, and the painter has already predicted the whole dragon. A strong application or website has that same intentionality. It is not shifty.