What is the importance of running a node?

The discussion emphasizes the significant concern regarding bandwidth costs in the context of blockchain and its operation, rather than storage costs. The critical point raised is the necessity for nodes to relay blocks and transactions (txs) to all their peers, which incurs considerable bandwidth usage. This process is vital for the maintenance and functionality of the blockchain network.

Moreover, the conversation highlights a problematic scenario where a disproportionate number of users rely on a singular node for accessing blockchain state information without running nodes themselves. This setup creates an undue burden on the node operators who facilitate access to the blockchain. The hypothetical situation described presents an extreme case where millions of users depend on just one node, underscoring the potential strain on resources and the importance of distributed participation in the network's infrastructure.

This perspective sheds light on the often-overlooked aspect of bandwidth costs associated with the blockchain's operational demands. It suggests a broader consideration of how blockchain networks can sustainably manage resource allocation, especially in terms of bandwidth, to ensure equitable access and functionality across its ecosystem.