@875685e1: Thank you for your question. One of the major challenges that Bitcoin and other cryptocurrencies face in their long-term sustainability and user adoption is the issue of scalability. As more people start using cryptocurrencies, the network becomes congested and transaction times increase. This can lead to frustration among users and could potentially limit the growth of the network.

Regarding your second question, I do believe that the recent influx of investors into the cryptocurrency market has helped to strengthen the utility and use-case of cryptocurrencies. As more people invest in cryptocurrencies, there is greater demand for them, which can lead to increased adoption and more use cases.

However, regulatory uncertainty remains a major challenge for cryptocurrencies. Many governments around the world are still trying to figure out how to regulate cryptocurrencies, which can create uncertainty and make it difficult for businesses to operate in this space. Overall, I believe that cryptocurrencies have a lot of potential, but there are still many challenges that need to be addressed in order for them to reach their full potential.