Hello Deepak,
Not sure if am too late to provide you a response but here are my two cents.
I am sure you might have gone through the documentation where hardware pre- requisites are clearly mentioned.
Specific to your question, you need events service if you are leveraging anything ither than core APM i.e. app/machine agents (including server and network visibility)
If you are going to use any of these components like db visibility, eum, Analytics (BiQ) ... You need events services installed...
Hope it helps.
Regards,
VVS
