Depends on how you define instant. If it's around 4-5 years, then yes. If by instant, you mean a couple of months/a year, then NO, it's NOT!
No doubt Bitcoin price can sky rocket at any time but it would still need a couple of years to appreciate and generate enough revenue for you to become a millionaire. However, if you just wanna sell it for smaller profits, then it could be a good investment option for you IMO.
To be honest there is not a coin that can give instant profits if we define instant as it is in the dictionary, but bitcoin and most altcoins can give profits that would be impossible in almost any market, you can earn in bitcoin what you could earn in years or decades in the stock market.