Hi Prashant,
depends on the definition how to use GRC. If users log in via SAP GUI transaction NWBC is required to start the business client. As Artem mentioned it is also possible to log in via hyperlink and in this case transaction NWBC isn't required.
What is your concern in this case? I don't see any issue in giving NWBC authorization to end-users even if they log-in via the hyperlink. The authorization inside the business client must be granted in both cases. If you simply authorize NWBC without any GRAC* authorization the user won't be able to see anything.
Let us know.
Regards,
Alessandro