smoke and mirrors
And if/when one of those low probability events happens, I will lose *one* file, or I will I lose *all* of my files on that node/instance/unicorn/<whatever cloudy instance thingy name>?
n-nines makes some sense for uptime discussions because you can relate it to a quantity of downtime. Your hosting provider claims a "5 nines guarantee" but they were down for an hour yesterday = they failed, read your SLA to see what compensation you are entitled to. Your cloud storage provider claims some made up number of nines and you lost data = what exactly (besides you're screwed if you have no other backup).