you can hit three nines even if you're down for 1.5 minutes every day, or ten minutes a week. It's really not as hard to hit as it sounds. For a compute heavy process that isn't end user facing (e.g. batch processing) it's perfectly viable.

https://uptime.is/

Also, most cloud providers don't guarantee five nines anyway. GCE SLA is 99.5 on a single instance, 99.99 on a region

https://cloud.google.com/compute/sla