- The throughput for BTC transactions is incredibly low and will not improve significantly in the future. In theory, its block-time is 10 minutes, in practice it can take as long as 20 minutes for a single transaction. This is in fact by design and deters attackers-- more frequent blocks make it easier for competing chains to get out of sync.
In comparison, Ethereum has 15 second block times, 3 minute verification. It fixes the security risks with an implementation based on GHOST.
- BTC mining is highly centralized and expensive. By 2020 it is estimated the amount of electricity used globally to mine BTC will be as much as Denmark consumes.
Ethereum already decentralizes mining by nullifying the advantages of using ASICs. And it will fix the energy consumption issue by switching from proof-of-work to proof-of-stake.
BTC will be seen as the first effort that introduced the blockchain to the public. But I doubt its longevity. We have witnessed this multiple times with tech. Consider:
- Personal computer (Altair, Apple, later Commodore, Tandy, Atari) - Internet (Altavista, Yahoo) - Social web (Myspace, Digg) - PDAs and mobile phones (Palm, Nokia)
In each of these scenarios, a second generation technology always came along and ate the lunch of the one first out of the gate. Why? Robustness (more use cases, platforms), efficiency/cost, and more user friendly.