Bitcoin's potential for widespread use by everyone on the planet raises several challenges and considerations:

1. **Scalability**: Bitcoin's current network can handle about 3 to 7 transactions per second, which is significantly lower than traditional payment systems like Visa, which can process thousands of transactions per second. To effectively serve 8 billion people, Bitcoin would need to scale significantly, potentially through solutions like the Lightning Network, which facilitates faster transactions off the main blockchain.

2. **Energy Consumption**: Bitcoin mining is energy-intensive, primarily due to the proof-of-work consensus mechanism. Critics argue that its energy use could be damaging to the environment, especially if the electricity comes from fossil fuels. Solutions like transitioning to renewable energy sources for mining could mitigate some of these concerns.

3. **Wealth Disparity**: Bitcoin's distribution is highly uneven, with a small number of addresses holding a significant portion of the total supply. This concentration of wealth poses challenges for its use as a fair means of exchange. Those who acquired Bitcoin early when prices were low have a considerable advantage, which raises questions about equity in a system that relies on these holdings.

4. **Economic Implications**: If Bitcoin were to be widely adopted, it could disrupt existing economic systems. It might lead to a deflationary environment, affecting prices and wages, which could disproportionately impact those with fewer resources.

5. **Adoption and Regulation**: For Bitcoin to be used by everyone, global regulatory frameworks would need to evolve. Different countries might have varying approaches to regulation, which could impact the overall usability of Bitcoin across borders.

In summary, while Bitcoin has the potential to be a global means of exchange, significant hurdles in scalability, energy consumption, wealth disparity, and regulatory acceptance must be addressed to achieve this vision. The fairness of its distribution and its environmental impact remain critical points of debate.