Be aware that while $previous is quite useful in providing exception chaining and better traceability, none of the internal php exceptions (e.g. PDOException, ReflectionException, etc) are called internally within php with $previous in mind.
So if your code throws an exception, recovers from it, then catches one of these internal php exceptions, recovers from it and throws another exception, you will not know the first exception that was thrown when calling getPrevious.
See: https://bugs.php.net/bug.php?id=63873