There is no better article than this one by Arman the Parman to understand what a node is and why it is important to run it.

When running a node, it is essential to run Knots (not Core). Parmanode runs Knots by default.

Bitcoin Core—particularly its upcoming v30 release in October 2025—poses significant risks to Bitcoin's integrity as a decentralized monetary network. Because it prioritizes non-monetary uses over Bitcoin's core monetary purpose, Core has become malicious and compromised. The key reasons include:

- Enabling Blockchain Bloat and Spam Overload: Core's plan to raise the OP_RETURN data limit (from 80 bytes to up to 1MB per transaction) and harmonize mempool policies with consensus rules would flood the network with arbitrary data, such as inscriptions, ordinals, or "shitcoin" transactions unrelated to BTC transfers. This bloats the blockchain, increases storage and bandwidth costs for node operators, and turns Bitcoin into a "dumping ground" for non-financial content, undermining its efficiency and scalability. Knots counters this with configurable anti-spam filters (e.g., `datacarrier=0`, `rejectparasites=1`) to reject such transactions at the mempool level, preserving resources without altering consensus rules.

- Threat to Bitcoin's Monetary Purity and Neutrality: By defaulting to relay massive non-BTC data, Core weakens Bitcoin's role as a peer-to-peer electronic cash system, as envisioned by Satoshi Nakamoto. This invites "parasitic" uses like embedding images, videos, or even illegal content (e.g., pornography or worse), eroding neutrality and exposing node runners to legal risks from unintended data storage. They warn it could "poison" the chain, making Bitcoin less viable as sound money and more like a general data storage platform. In contrast, Knots empowers users to prioritize monetary transactions, viewing Core's changes as an "attack on Bitcoin" that harms the network's success.

- Developer Centralization and Ignoring Community Consensus: Core developers imposed changes without broad user input, silencing dissent (e.g., closing GitHub discussions, dismissing feedback), and enforcing "TrustMeBro" defaults that limit user sovereignty. This creates a "culture of control" where a small group dictates policy, potentially captured by corporate interests favoring data-heavy innovations over decentralization. Knots, as a derivative with extra features, serves as a "backup" to prevent single-point failure and promotes multiple implementations for robustness. The rapid growth of Knots nodes (from ~400 to over 4,000 in 2025, ~18% of the network) reflects this protest, signaling eroding trust in Core.

- Risk of Network Fragmentation and Long-Term Harm: While Core claims its changes foster innovation (e.g., digital art verification), they'll centralize power among miners/relays who include spam for fees, raising costs for everyday users and deterring node adoption. This could lead to chain splits reminiscent of past forks (e.g., SegWit 2017 or BCH), fracturing the network and inviting regulatory capture.

Ultimately, Core is "hostile to Bitcoin's success". Core v30 is a tipping point that sacrifices Bitcoin's antifragility for permissive policies, potentially dooming it to bloat, irrelevance, or capture—while Knots restores user control and aligns with Bitcoin's original ethos.

As Uncle Rockstar Developer notes, Core v30 encourages the use of Bitcoin as a tool for the expression of vanity, while Knots preserves its use only for monetary purposes.