No, you can still use the other features of Nav Prime without applying for a Nav Prime Card.
Nav Technologies, Inc. is a financial technology company and not a bank. Banking services provided by Thread Bank, Member FDIC. The Nav Visa® Business Debit Card and the Nav Prime Charge Card are issued by Thread Bank pursuant to a license from Visa U.S.A. Inc. and may be used everywhere Visa cards are accepted. See Cardholder Terms for additional details. All other features of the Nav Prime membership are not associated with Thread Bank.
With regard to credit building features: scores are calculated from many variables; some users may not see improved scores. The Nav Prime Charge Card is a business financing product and may not be used for personal, family or household transactions.