No, selecting a checkbox to use the database admin as the service account is not a recommended or required configuration when implementing a source that uses a JDBC connector. Typically, for security and least privilege, a dedicated service account with only the necessary permissions to read and manage identities within the database is used. Granting database administrator (DBA) privileges to the service account introduces unnecessary security risks and is against best practices.
Reference:
SailPoint IdentityNow JDBC Connector Configuration Guide.
SailPoint IdentityNow Best Practices for Service Accounts Documentation.