> I have no idea what "1 vCPU" means in this context but severely doubt it even means "1 hyperthread" (...)

I don't believe anyone looking into this sort of offering is expecting even or looking for "1 hyperthread". Hell, obviously they aren't looking for performance. I mean, they are marketing this as a node to test scaleway's services and put up small websites. I'm sure that performance-minded customers are planning to run anything performant on a 1vCPU instance with 1GB of RAM.