Are you referring to the "Splunk Add-on for VMware"? I believe the "Splunk Add-on for VMware ESXi Logs" only provides Splunk knowledge objects like field extractions.
If so, then yes you can use the heavy forwarder as a data collector node. It defaults to using 10 workers which can be adjusted depending on how much load you expect and how beefy your machine is. I would recommend monitoring the CPU and RAM usage on your heavy forwarder after activating it, to ensure you are within limits.
If you have extra CPU and RAM, then you can also install other apps and services on the heavy forwarder.
