How many became Millionaires by using other payment methods like PayPal / Fiat cash / Credit cards ?
Not a good comparison. PayPal & Co are nothing more than services that allows people to transact with fiat in digital form, and that's really it. Fiat on its own will not do anything other than losing value, and thus make you end up with less wealth despite the quantity of your wealth being the same as before.
The fact is, Bitcoin have also protected some people's wealth, when their governments and banks wanted to destroy it. {Greece / The 2012–2013 Cypriot financial crisis.........}
That I fully agree with. I personally have a large part of my wealth locked into Bitcoin for the sole purpose of keeping it outside the banking and governmental system.