[mfonda]

This information is often communicated by the type of the exception itself. Maybe it timed out: TimeoutException. Maybe the connection was refused: ConnectionRefusedException. Maybe it returned 404: NotFoundException.

Depending on the specifics of how it's handled, you may or may not need the actual error message. For example, in production you may want to implement some sort of logic (retry, display friendly error message, etc.), none of which needs the actual error message.

This feature isn't unique to PHP. Other languages with Exceptions, for example C# and C++, have this exact same feature.