It's a scarce resource, deflationary in nature. Of course it's an intrinsic property. One could've predicted that before Bitcoin was even launched if Satoshi described the limited nature of the currency.
In fact, the earliest big investors DID correctly predict that reality. Today we call those people "smart money", and many of them are "Bitcoin millionaires".
They took a risk; it appeared most probable at that time that a BTC would eventually be worth $0. It is not a fundamental law that Bitcoin is deflationary.
In fact... right now; it is inflationary in the sense that new Bitcoins are still being added to the system.
Just because the supply is limited does not mean it will be deflationary, however.
This depends on the amount of economic activity, with regards to BTC changing hands, which affects the supply and demand of BTCs.
I would like to point out --- that not even 10 million actual BTCs necessarily have to exist to support an annual GDP of 10 billion BTC, as long as only consumers are using them and merchants are not holding the BTCs; the BTCs get sold right back to the exchanges, and effectively, the exchanges eventually start working like central banks...