https://blog.cloudflare.com/announcing-wasi-on-workers/
I assume the merit for cloudflare is lower overhead cost per worker than if they had done something more like AWS lambda. Explained better than I can, here: https://developers.cloudflare.com/workers/reference/how-work...
It does currently present a lot of restrictions as compared to what you could do in a container. But it's good enough to run lots of real world stuff today.