In a payment system, units are required. Satoshi chose to call them bitcoins. (S)He didn't create value out of thin air. Whoever wanted a payment system that followed this consensus scheme could join and be part of its distributed ledger.
It's nothing, but a ledger of debts.
Or let me explain it another way.
Imagine a friend saying to you: "You own 10 Ferraris and 50 luxury apartments in Hawaii." Of course, you don't own them, so you would probably laugh at such a statement. Now imagine an anonymous guy, let's call him Satoshi Nakamoto, saying to you: "you own a revolutionary digital asset, digital gold, money of the future." You would also probably laugh at such a statement because you know that you own nothing of a such. But, you see, millions and millions of people around the world believe Satoshi. They believe to own some revolutionary digital asset. And the only reason they believe it is because Satoshi told them so. They even spend enormous amounts of electricity to keep Satoshi's statements stored in database. And they even pay an enormous amount of money to transfer these statements from one name to another. Currently, we live in a time of a collective madness. Madness, in which an anonymous author wrote a computer program through which he is saying something to people. And people blindly believe him.
To better understand what's going on, let's go back to your friend. Imagine that your friend formally writes his statement into a database as data. First column in this database would contain owner's name, the second quantity of asset, and the third name of asset. So we would have something like this: "John Smith", "10", Ferrari. The second row in the database would be this: "John Smith", "50", Luxury apartment. So this is your friend's statement stored as data in a database. Now, would such transformation of verbal statement into data mean that you became the owner of Ferraris and apartments? That you magically became rich? Of course not. That would be ridiculous. Just because your friend stored his statement into a database as data, that doesn't make the statement true. It is still false. It still contains fake quantity data on the said assets. But in the current bitcoin madness, Satoshi's statements in the form of data, are considered true. And they are believed blindly. Namely, this anonymous guy, Satoshi Nakamoto, wrote a computer program through which he is saying to people, who performed a certain job, that they own a specific quantity of a revolutionary digital asset called Bitcoin. The job performed is the maintenance of a database that contains quantities of Bitcoin and virtual addresses of people who "own" Bitcoin. The database is called blockchain, while the maintainers are called miners. But now comes the fun fact: Bitcoin doesn't exist. The "revolutionary digital asset" is fictional. It is as fictional as the Ferraris and luxury apartments in the statement of your friend. And although we at least know what Ferraris or luxury apartments are, here we have some "revolutionary digital asset" but nobody even knows what this asset is. Nobody knows to what thing in the real world blockchain quantity data belongs. Only name was given to it: "Bitcoin". Generally speaking, quantity is defined as the amount of something, so here, "something" is Bitcoin. But besides the amount and address in the blockchain no asset exists anywhere that is in the ownership of address holders. And if one were to ask them where is the revolutionary digital asset, where is the thing that has quantity written next to their addresses, they wouldn’t be able to show it. That is because Bitcoin is fictional. It doesn’t exist. Their ownership of Bitcoin is imaginary the same as your ownership of Ferraris and apartments.
All that people are doing in the Satoshi's scheme, is sending and receiving quantities of fictional Bitcoins. And every such transfer is recorded in the blockchain. So the whole scheme, is as nonsensical as believing that just because your friend stored his statement into a database as data, that you now own Ferraris and apartments. And because you "own" them, you believe you are rich. How rich? Well if you scam a guy to whose name in a database you would transfer quantity data on two nonexistent luxury apartments, and he would pay you $1,000,000 for the transfer, then you would have (50-2)*$500.000 or 24 million dollars worth of "assets". This is how "rich" you would be. You would be "rich" because your friend made a fantasy statement and stored it into a database. This the essence behind Satoshi's scheme. People believe that they are rich, that they own some revolutionary digital asset, just because Satoshi’s computer program makes fantasy statements in the form of quantity data. That's the collective madness we currently live in. And because people have fall for this madness there is now the explosion of authors who create computer programs through which they make such fantasy statements. Only names given to nonexistent assets are different.