Since the CVM's OS isn't fully Hyper-V integrated, we don't see memory demand from the hypervisor (this is the only benefit I see from leaving dynamic memory enabled on a VM with all values set the same).
As an explicit downside, since we're using Dynamic Memory on these VMs, we lose the vNUMA featureset (not that a 32GB VM is likely to benefit from it).
Best answer by mmcghee
Sorry for the delayed response here. As you mentioned we do not benefit from vNUMA and the current configuration was a workaround for a Hyper-V bug. We're looking at changing this back to static in future releases assuming the original issue has been resolved.