If you think about an object storage platform, much like with YouTube, traditional load balancing is a really bad fit. No two requests are even remotely the same in terms of resource requirements, duration etc.
With an Object Storage service like S3, no two GET or PUT requests an LB serves are really the same, or have the same impact. They use different amounts of bandwidth, pull different at different speeds, different latency, require different amounts of CPU for handling or checksumming etc. It didn't used to be too weird to find API servers that were bored stiff, while others were working hard, all while having approximately the same number of requests going to them.
Smartphones used to be a nightmare, especially with the number that would be on poor signal quality, and/or reaching internationally. Millions of live connections just sitting there slowly GETing or PUTing requests, using up precious connection resources on web servers, but not much CPU time.