Funny how almost everyone seems to be discussing the diagram and not actually reading the NIST paper first hand.
And then nitpicking over the very definition of what block chain is. But then saying 'bitcoin' 'ethereum' 'git' and 'merkle tree' over and over and over.
Given the title of the thread, and the availability of the actual text, I suggest everyone take a quick read first, then come on back. It is only 50 pages.
This is one of the sources provided in the NIST Report appendix of references.
PDF page 53 of the document with canonical URI of , resolved by the doi.org resolver  to a pdf with a NIST URL .
pdf of the document: https://nvlpubs.nist.gov/nistpubs/ir/2018/NIST.IR.8202.pdf
Via DHS and NIST, the answer is on 42:
Is that page number a coincidence? I wonder.
Anyway, here are a bunch of other decision trees as well:
Cutting through the noise:
If it is centralised, i.e. one entity controlling write operations, you don't need a blockchain. See e.g. the "when to use a blockchain" flowchart on page 41 (53 of PDF) in the "NIST: Blockchain Technology Overview".
Note also that many systems are sometimes erroneously referred to as using blockchains, for whatever reason (misunderstanding, marketing, etc.). Leaving aside the debate about how decentralised it is, the project you mention has a distributed ledger, but uses a Directed Acyclic Graph (which they call a tangle) rather than a blockchain. Similarly "permissioned blockchains" or "private blockchains" aren't really blockchains in the strict sense because they don't need a consensus mechanism (indeed many now call themselves Distributed Ledger Technology systems).