It’s back-to-school shopping time. This year, shoppers are expected to shell out almost $28 billion on everything from e-readers to crayons, from backpacks to sneakers. More of that spending is happening online — roughly 30% this year, up from 23% last year, according to the same study.

One big reason for the growth in online sales? Amazon’s “Prime Day” in July, says Andrew Lipsman, an analyst with eMarketer.

“Amazon is really leaning into the full season and ramping up a lot of their marketing and advertising efforts,” he said.

The ads are full of kids and backpacks and all the stuff that goes in them. And parents are clicking, said Deloitte retail analyst Rod Sides.

“I think a lot of it comes back to convenience,” Sides said. “Consumers looking to save time.”

But the big brick-and-mortar shopping trip had its uses for children, according to Allen Adamson, a business professor at NYU.

“It does diminish the experiential dimension, which is an important part of getting kids mentally out of the beach mode and into the classroom mode,” he said.