You are mostly right but devops people should still play around with the newest tools to form their own opinions.

It's complicated.

I wouldn't stop considering containers per-se (SmartOS zones/FreeBSD jails are fine!) but the whole tooling surrounding the management of Linux containers and corresponding images is still in the "cambrian" phase. Security issues and the general over-selling of the technology (Docker and CoreOS especially are almost too good at marketing their products..) shouldn't discourage you to play around with "those toys" though. Even for certain production scenarios there is a bunch of setups which work fine already (RedHat's OpenShift platform comes to mind).