Every "cloud" computer is on-prem for someone, and "private cloud" has been a term for at least a decade to refer to "API-based provisioning of resources like with a cloud but in your own data centre/office" that may not be "technically" a cloud but carries the meaning clearly for anyone in the business.
What they're selling is building blocks for private/hybrid/public clusters that may or may not fit your definition of cloud depending on where they happen to be located but where what the term signifies is that it is built to be a building block of a cloud setup that includes features above and beyond a "regular" server to provide what most people tend to associate with a cloud. That is, you're getting APIs to spawn virtualized compute and storage, rather than having to install a hypervisor and management APIs etc. and combine the resources into a cohesive whole yourself.
My guess is that most of them will end up being sold to either hosting providers to provide cloud services to their customers or companies large enough to operate their own data centres where the IT department will use them to offer cloud services to other parts of the business, where the term really is not misleading anyone.
It's too big even for most "private clouds" in smaller companies, because they tend to be too small to be able to order by the rack even when there are APIs etc. offered to developers to provision compute and storage (e.g. years ago I used to operate a hybrid cloud setup with a ~1000 or so VM instances across several countries, and while we had several racks worth of gear we physically owned in aggregate, we didn't have any full racks in any individual location).