Whether surely to use the intermediate forwarder for collection of metrics?
I want to collect directly metrics on Splunk Enterprise.
Here by intermediate forwarder I am assuming the "Data Collection Node".
So DCN is always required for collecting metrics. This is where the scheduler sends jobs to collect all data and then DCN forwards it to the indexer.
Also there is no way to collect directly? Why this excess layer if I don't want it?
You can not miss this extra layer of DCN. However you can configure the DCN on same machine where you have your main app.
You need to add the same machine details as the DCN node in your collection configuration. As all the required components are already present on main app (SH), so this can be implemented.
But this can be used in case of really small environment else you may get performance issues. In this case you will the actual benefits of Data Collection Distribution.