The strength of bitcoin comes from its infrastructure.
Bitcoin has become a payment method in many online shops, like paypal or credit card.
That shows the economy has gained a certain trust in bitcoin.
There are exchange services and whole businesses developed around bitcoin.
Recently bitfinex was hacked, but it just scratched the price of bitcoin a little bit.
I say that bitcoin became strong in price and reliable as a payment method.
Strongly agree, bitcoin has strong foundation and keep growing every year. Good as online currency that has been used worldwide, and will continue expand in every country.