The OP is neglecting to address the fact that a blockchain is a distributed ledger and Bitcoin is simply a currency that has all tx's stored on a blockchain. These days there are MANY applications using blockchain tech and most have nothing to do with Bitcoin. Given that, their title for this topic is wrong as Bitcoin is a currency. Period. While its format allows for inclusion of text and other data the Bitcoin blockchain was designed solely for handling currency.
As the OP mentions, those blockchains are mostly for records keeping. From food production and distribution, civic lighting (streetlights etc), to civil records such as deeds and other property records, taxes, etc you will find blockchain tech used where such data was once stored in a database. Why the change from using a traditional DB? Simple: Security. A normal centralized DB can be broken into and easily modified. A distributed blockchain database cannot be hacked so easily.
I asked in the previous article, what exactly is Bitcoin? What are the essential attributes of Bitcoin? My answer is that if all external factors are removed, Bitcoin is a distributed database.
You were also trying to say "Bitcoin comes first and blockchain comes later".
The fact is that you can not separate different aspects of bitcoin. Bitcoin is a combination of multiple technologies and if you remove one it will cease to exist. In other words if you "remove all external factors" bitcoin will no longer be a distributed database either simply because it wouldn't have any reason to exist.
This database exists because bitcoin is a currency that has a value and miners mine it and nodes store its blockchain which can be used as a distributed database. All go hand in hand.
When we know that Bitcoin is a database,
The problem when you change the definition and selectively use only one characteristic is that the definition starts to fall apart.
A database by definition is storing raw data that can be interpreted anyway you like and can be changed very easily. Neither of which are true in bitcoin. You can only interpret the "data" in blockchain in one way, as blocks and transactions, and you can not change them freely since they are protected by cryptography.
A database also has no reason to be immutable, in fact the basic characteristic of a "database" is mutability.
I also wouldn't rank them either, saying this comes first and that second. Bitcoin is a whole system that has all of the above at the same time.
There is no single way of giving the perfect ultimate defujitio if anything. And there are different approaches to definitions themselves which focus on genesis, function, main attributes or other things. Defining Bitcoin primarily as a ledger means focusing on the underlying technology at its core. If we define Bitcoin as a currency, we focus on its function. Both are essential, and why choose between them if we can combine them? And then, the definition would be something like this: Bitcoin is a blockchain-based currency that can be used for trading, long-term investments and as a medium of exchange.
Thank you for your wonderful views, let us further clarify the basic properties of Bitcoin. As everyone has said, it is difficult for us to have an ultimate definition of Bitcoin: what exactly is Bitcoin. Bitcoin is formed by the collection of a variety of knowledge. From the perspective of different disciplines, there are different definitions. As everyone has said, Bitcoin is a whole and cannot be separated. The reason why I listed them separately is to explain them from different angles so that we can understand that Bitcoin has different attributes. However, whether it is a blockchain, a ledger, or currency, they are all integrated. Together, they formed the Bitcoin network and built the Bitcoin ecology.