You're right, that mode provides process crash recovery, not power-loss durability. The benchmark compares it against fjall’s equivalent buffered-WAL mode.
Word choice matters. Defaults matter. People will go "well it says durable right here" and while arguably, yes, they should RTFM, it would still be great if tool-builders did not set the shotgun's default state to State::AT_FOOT. It would be nice if every paragraph of technical writing that I have to do need not be burdened by a thousand asterisks of "durable in this context means something other than durable".
Agreed. Good design is when the things do what you expect them to do without reading the manual, don't reuse wording with other meaning in the wrong way. That way if you do encounter nee wording, you know you should read the manual.
Indeed, a common enough pattern for etcd is to run it backed by a RAMdisk and have multi-az availability + periodic backups + tolerance at a business level to be OK losing some recent data.
