[parhamn]

I think the key benefit brushed on by this article is the potential 10x improvement in access speeds (which has many applications, beyond reducing your s3 op charges).

> S3 Express One Zone can improve data access speeds by 10x and reduce request costs by 50% compared to S3 Standard and scales to process millions of requests per minute.

[haimez]

10x reduction in latency, higher storage costs with lower access costs (SSD instead of spinning disks). So high I/O, small files situations (with no need for cross AZ access) are where the benefits can be found.