for someone who has spend years in stocks market and traded them so he has a lot of experience: stocks
for someone who has spend a long time in bitcoin market and traded bitcoin so that he is familiar with how it works: bitcoin
for someone who has no prior trading experience and has never been in any market: neither!
This response sums it all. The higher the volatility, the higher the profitability, vice versa. All in all, experience is key.
Before you consider trading at all, be it Bitcoin or stocks, you need to learn the intricacies of trading before committing money into it.