I think at 0.1, it could be a decent one to have. With the current forecast of BTC price, your 0.1 now might be tens of thousands in the future but I don't think it will make you a millionaire.
If the price of 1 bitcoin now is $56000, the price increased small from when I posted $54000, it will only take 20x to move up to $1 million. Definitely this is possible, but it will only happen after a very long period of time like 4 or 5 years. But for 0.1 bitcoin, it will take 200x, more time needed for this, I can not have this in plan at all but 1 bitcoin to reach $1 million is still very possible but it will take time.
Just invest what you can afford to lose and by that even if it goes down, you will be okay. And if its goes up, great return is possible.
If it is trading which is riskier, I will agree but this is holding, bitcoin holders will never lose if they are patient. Even better to invest more if the price is decreasing because it will increase back and beyond.