The way I interpret it: an integrated stack of compute, storage and networking hardware and monitoring software that you can plug in to your data center (owned or colo) and can e.g. deploy Kubernetes to, and then use as a deployment target for your services.
The main USP: you own it, you're not renting it. You're not beholden to big cloud's pricing strategies and gotchas.
Secondary USP, why you buy this rather than DIY / rack computer vendor: it's a vertically integrated experience, it's preassembled, it's plug and play, compatibility is sorted out, there's no weird closed third party dependencies. Basically, the Apple experience rather than the PC experience.
The main USP: you own it, you're not renting it. You're not beholden to big cloud's pricing strategies and gotchas.
Secondary USP, why you buy this rather than DIY / rack computer vendor: it's a vertically integrated experience, it's preassembled, it's plug and play, compatibility is sorted out, there's no weird closed third party dependencies. Basically, the Apple experience rather than the PC experience.