With 10 BTC I can buy like 20 iPhone? 
No you probably couldn't actually buy 20 Iphone 5s for 10 BTC, Do the math.
And they probably wont have the flappy birds game on since it cant be downloaded anymore.
They are worth whatever someone is willing to pay for them ( i am interested to find out how much that is )
10 BTC = 7k USD = RM23k
I can buy 20 iPhone 5 with that amount in Malaysia.
I have iPhone 5S, iPad and Android. All installed with Flappy Bird