> I think I missing something
Koolaid.
Koolaid.
You keep the ability to exercise a fair amount of control, easily, and clearly. And you don't sit inside really opaque execution environment.
Sure, the scaling and provisioning of those Docker containers is opaque, but I'm much more willing to deal with it at that level.
The flip side - so long as its a service and not a job, who cares? :D