This is just an opinion and think one of the biggest challenges is regulatory uncertainty. There are many global measures in place to regulate cryptocurrencies, and these may impact the rate of adoption and usage of Bitcoin. Another challenge pertains to scalability issues. This is because a lot is left to be desired regarding improvements in the transaction capabilities of Bitcoin in handling volumes. Besides, the unstable nature of Bitcoin's price may not make it ideal for a store of value. Indeed, this takes sustained stability to reach such mainstream adoption. Security concerns relating to the wider environment of cryptocurrencies and the ecological footprint of Bitcoin mining are also issues of some relevance. Education on the benefits and risks would serve to increase the adoption of Bitcoin. And if that were not enough, it has to compete with other digital currencies. Despite all these challenges, in the growth of community interest and the integration into financial products lies great potential for Bitcoin. If all those mentioned above are properly solved.