Venkata,
The etc/*.p12 files are for client applications that you can find in WAS_HOME\bin like startServer, stopServer, synchronizeNodes, wsadmin,.....
For example you can use wsadmin to connect to localhost but you can use to connect to remote machine. You need to have remote machine certificates in your etc/*.p12 files if you haven't you not able to connect.
I dont't remember well (i need to test) but etc/files are not synchronize with nodes (when you launch from adminconsole)
Hope this helps.
Regards