Yeah, unfortunately it is up to the hub manufacturer to integrate OTA updates into their hub. We have been discussing with SmartThings this capability and are trying to work with them on it. The reason that our instructions show the method that they do is that it is the most straight forward option with the fewest technological hurdles that can apply to the majority of users. As an alternative you do have a few options (for next time).
As @jtronicus mentioned, you can use the replace method that SmartThings has. There is one additional thing to note for this though. When you reset a z-wave device many newer devices (last few years) will send a “Device Reset Locally” report (as per z-wave specs) to the hub before they reset. The hub is supposed to remove the node at this point. SmartThings will respond to this report by removing the device. So, I recommend that you power off the SmartThings hub while you reset it if you want to use the replace option.
The second option is to include the Z-stick into your SmartThings network as a secondary controller. You put the SmartThings hub into inclusion mode and click on the “Learn” icon in the PC Controller Software. This should obtain the S0 security key that will be needed to update the switch.