Note: if you want to conflate “containers“ with an entire job management and scheduling system (“k8s”) then you’re not actually talking about the current target customer for VMware.
None of those matter in the slightest with containers. Why would you need to reallocate hardware resources when the containers can run on another piece of hardware? You would snapshot the relevant storage, not the whole OS and kitchen sink.
VMs as an intermediary between hardware and containers is just a waste of resources - both directly (RAM, CPU, storage to run a useless OS with no benefit) and indirectly (all of those VM's OS needs maintaining and patching).
It's basically a hold over from the olden days of "everything is a VM".
Sure, most of what we do is very cattle and we could run on bare hardware but why not take advantage of easy to add flexibility.
Your "machine for testing" would be a container. Decommissioning a container is easy. Decommissioning a physical machine only happens when it's obsolete.