How Canva saves millions annually in Amazon S3 costs
canva.dev
canva.dev
As a feat of engineering...kudos. But engineering savings might not translate into user benefit. It would be interesting to see analysis from the customers' POV.
Their point is that storing older objects on IA saves money in exchange for latency. A user who tries to fetch a very old project out-of-the-blue can always live with very minor initial delay, after which it will stay on the instant access tier until timing out again.
The arc of my curiosity is, too often we deliver technology "improvements" that don't necessarily improve the user experience.