It’s a significant deviation from what I would expect from a disk oriented database. So I would definitely expect it to be well documented, along with the reason for it, why the developers believe it is a reasonable (or even safe) choice, what assumptions went into that (such as availability of uninterruptible power supply) etc.

Additionally keep in mind that with EBS most people probably use network attached storage and fsync involves the network. Outage doesn’t just mean power outage, it could also be a network issue.