You're asking why someone who uses CentOS hasn't gone with Helm charts?

That's like polar opposites of stability and bleeding edge.

I was curious what drove the decision to deploy that way. I was under the impression most new applications being developed today would choose a more modern deployment method. There’s a lot to maintain in a VM image like that, containers just seem easier to me. Helm chart or otherwise

The amount of maintainance with virtual machines images or container images are mostly the same nowadays.

I will argue that there is less maintenance when handling virtual machines images, because it uses less bandwidth and need less tooling around it comparing with container image based infrastructure.

But in general both are nothing more than the golden image concept.

>a Helm chart

As a sysadmin i have never heard of this and es tun 800 VMs.

It's a bundle of jinja2 templates for YAML files defining Kubernetes API resources. There's an accompanying application, Helm, which applies values to the templates and handles the interaction with the Kubernetes API.

Helm uses Golangs built-in template language which is definitely not jinja2 compatible.

Basically the same thing: templating.