Bitcoin has been able to grow 4x its value since January, if you know any fiat option that allow to make such results let me know i might invest 1 dollar over it, crypto has already proved its value and just showed a part of its potencial, and believe me there is still much more to be found over it and better results will be achieved in the future.
That is the beauty of bitcoin that it row more and more than any other fiat currency. As you said, it is so true, bitcoin have increased at so high rate 4X so what you expect in upcoming years do it not go faster? Yes it will. So it is best investment to make.
We can't just predict that next year that the price would also be 4x as what it is this year. Anyway, I agree that it is a good investment especially in the long run considering that the demand is continually increasing so thus the popularity that leads to it. It has a huge market support and distrubuted even more across the globe making the market more solid.