so you are saying you are buying a coin with 7 full nodes? i do not think you really understand blockchain ....
Pretty clear who doesn't understand blockchain. It's not about decentralisation for decentralisation's sake. It's about how to create a trustless system. If you can do that with fewer nodes, then making the system more centralised is irrelevant. Why? Because it's about removing the human element from the equation (or mechanising it through incentives). Large-scale decentralisation is one way to do that. There may be other ways!
A ridiculous example would be a completely tamper-proof node (a black box) equipped with automatic self-defence systems - anyone who tries to meddle with the box or its Internet connection dies instantly. In this case, just one node would suffice to provide a trustless system (provided all the software has been independently audited).