Bitcoin is a currency. You cant say money is gambling itself. But if you invest your money and convert it into bitcoin, now it is gambling. Because you take a risk investing your money to a volatile currency hoping it would rise up in the coming days, but you know it might also drop. There is still win or lose in it, so basically its still gambling. The process is gambling, not bitcoin itself.
That's right, Bitcoin itself is not a gambling it's a currency to be and is used. But we got to admit that almost all bitcoin related industry is a gambling from trading, investing and gambling itself and other forms of bitcoin transaction. But comparing to gambling investing and trading bitcoin is different, well it is really considered a gamble because of the risk it has but in bitcoin it has high chances of payout just need the right knowledge and experience and cyrptocurrency.
As your said, Bitcoin is really a gamble because nothing can increases the value fastly and reaches to high price as Bitcoin at now.
Old bubble in the past can not compare to Bitcoin growth.