Although permits for Umrah are rarely checked by the Authorities in Makkah, it is always best for you to make the booking which takes only a few seconds more on the app as you can see above.
Lately authorities at airports have requested to see the umrah permit from nusuk in order to allow pilgrims to carry zamzam especially at jeddah international airport.
So please just book your Umrah slot!

TIP: Take screenshots of your bookings so that it is more convenient for you on the grounds in case the app doesn't load up or you do not have any data.