The option to view or manage zones via Web Host Manager is not offered in cPanel DNS-Only. Typically, you would sync the zones from another cPanel server to the DNS-Only server, and thus editing/viewing the zone should occur on the cPanel hosting server. That said, feel free to open a feature request if you would like to see this feature implemented:
I wouldn't want to edit zones on the DNS-only server but it would be good to be able to view the zones on there without using CLI or a dig/nslookup command.