More than a few reasons:
* Not surviving updates is not a bug, it's a feature: we have no guarantee that a change in Nickel's behavior won't break KFMon in subtle or not-so-subtle ways, and, in the worst case, that could lead to a boot loop or a soft lock.
* You have no guarantee that the old script could even allow the updated system to boot sanely.
* You have no guarantee that the update process will handle a permission error sanely

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