Yes, the billing is specifically targeted around per-second execution. The containers can start within a few seconds, they allow for customization of CPU cores and memory, and they allow you to focus entirely on your container without having to worry about any VM management. Traditional VM-based infrastructure is still the way to go for long-running applications. This just opens a new avenue into using containers in the cloud.
Off the top of my head, this could be used for backups, database migrations, auditing software, report generations, email blasts, CPU/memory intensive operations... The possibilities are endless because the execution layer is just a container, so you're not limited on what exactly is being run inside it.