Dataguard Broker is best used in a configuration where there is a separate machine used to monitor the up/down status of the components.
For example: using broker on the primary would not help in event the primary was down or unavailable, the same holds true for the standby. Therefore it is best to understand the requirements for additional resources to plan for this. Many companies do not use broker for the very reason of this critical configuration.
A common misconception is that DGMGRL can be used to create new standby databases. Here is an excerpt from Oracle’s website:
Although DGMGRL cannot automatically create a new standby database, you can use DGMGRL commands to configure and monitor an existing standby database, including those created using Enterprise Manager.
The Data Guard command-line interface (DGMGRL) enables you to control and monitor a Data Guard configuration from the DGMGRL prompt or within scripts. You can perform most of the activities required to manage and monitor the databases in the configuration using DGMGRL.