bitcoind can function either as P2P node + RPC server, or as RPC client.
If you run "bitcoind help", you send the RPC command "help" to the RPC server, and get as response the supported RPC commands by that server.
If you run "bitcoind --help", you get information about the command-line options supported by the actual binary you are running.
ahhh thanks for that. Was confused about that.