The command line query contains the additional \'to escape the character because the whole string is surrounded by '. So the command line string will only work directly at the command line and at the HANA studio the query you posted will be the result.
If you run the command line string does it give you the same result as the query directly form the HANA studio?
I remember, there were a problem back a few moths where the string got problems between some OS versions and HANA versions and the simple fix was to alter the special characters. I will try to find the thread.
the hdbuserstore is more secure in general and is easier if something changes at the database version. If you change to a scale out system your DBA doesn’t care about keep the users synchron along the whole landscape. I never used the monitoring with user/pwd connection. To get more information always use the direct call of the plugin with the --debugoption.