The Nintendo Switch's bootloader aka the part that controls the boot-up process for the console checks the number of fuses burnt and compares it to the current firmware. If they do not match, it will either prevent the console from turning on or it will burn them to compensate. While both Hekate and SX OS V1.2+ not only bypass the fuse check entirely as substitute bootloaders but also prevent fuses from being burnt, this is not enough protection against burning fuses during system updates. The reason for this is because when you update the Switch normally, it reboots the console so the Switch has a chance to burn fuses. Even if you initially boot the console with either Hekate or SX OS V1.2+, when you update normally within the Switch, the Switch's bootloader will take over when the console is rebooting after the update. Therefore, the guide not only has you install AutoRCM as a means to prevent you from accidentally booting the Switch normally which will burn fuses, but also has you install the update entirely offline. It should also be worth noting that updating removes any and all forms of AutoRCM which the guide has a section on how to recover it to prevent your Switch from trying to burn fuses.
In theory, you can update without following the tutorial and instead using the official way while not burning fuses IF you can stop the console from turning back on after it updates successfully. This is a very user-oriented window that if you miss will permanently burn the fuses and is a risk you can take should you acknowledge it. Another problem is that once you do manage to turn off the console with the correct timing, you have to ensure from that moment onwards that you will boot your console from RCM only because it will burn the fuses if you turn it on normally. This means you must have some means of inducing RCM with 100% confidence or you risk burning your fuses. AutoRCM cannot save you in this case as it will be removed during the system update and can only be re-installed via RCM.
Lastly, while the guide is rather lengthy, it is nearly 100% noob-proof and will prevent you from burning any fuses. It also details each and every step in such a way that anybody can follow it, even if they have no hacking experience whatsoever.
