"High" transaction fees and the future feasibility of micro-transactions. Transaction costs represent inherent real-life constraints on scalability and resource availability in the network. It costs money to host fully validating nodes. There is no such thing as a free lunch. Bitcoin was able to achieve zero-fee transactions because the cost was subsidised by the mining reward and bitcoin's value increasing at a faster rate than resources were being consumed. It is not because of the block size limit; as you scale up, the amount of competition for space will also grow. We will see increases in the block size eventually, and add second-layer systems like Lightning Network.
Bitcoin is a dynamic and evolving system and the rate of innovation has exploded over the last few years. Appointing third parties to determine which transactions are "spam" opens up opportunities for censorship. Sufficient fee is a market-based mechanism. Even if your transaction doesn't have sufficient fee at the time, it could still be confirmed later when there is less demand for the network. Transaction malleability. Segregated Witness is the best scaling that exists right now. For many miners, it represents a potential loss of profit but only if they're not willing to evolve their software and participate in payment channels. If we choose not to expand the scale of the network, that doesn't mean Bitcoin stops working; it means that Bitcoin will specialise in high-value, global, secure transactions. Nobody gets to decide what Bitcoin and we don't know what it will become. The recipe has been replicated in other cryptocurrencies, and that's how a market should work -- allowing the full forces of evolution and specialisation to operate.
Good post.
Just one thing, I run a full node and it really costs almost nothing. I run it 24/7 on an old computer and electric bill shows no increase. More info here: To Node Or Not To Node if you're interested.
Anyway, liked your post.
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