In practice, until you're at a certain scale, software bugs are more of a threat to your availability than hardware failures or maintenance downtime, and the cloud does nothing for you there (in fact, the additional complexity is likely to make it worse). Modern hardware is pretty reliable, more so than a given ec2 instance, for example.

Often, software bugs cause issues with machines (uncontrolled logging overwhelming disk space and killing everything, instead of objectstore absorbing it, or a memory bug that kills the process over a few days and needing manual or custom monitoring scripts instead of k8s handling this until its root caused, and so on)