Yes, this is literally it. It simply comes down to supply and demand and that's where it derives its value from. It's not really beyond logic and is quite simple really. The more the demand there is for bitcoin the rarer it becomes and therefore more valuable. If half the world wanted to buy bitcoin then it would push the value through the roof because there is only a finite and limited supply of it. That's why if you want bitcoin to succeed and grow in value then you should tell everyone you know or meet about bitcoin because the more people that get on board the more valuable it will become.