According to Alice und Bob, parachains and rollups are both scaling solutions, but they differ fundamentally in architecture and trading implications. Parachains, as implemented in the Polkadot ecosystem, are independent blockchains that connect to a central relay chain, enabling interoperability and shared security, which can lead to diversified asset trading and cross-chain liquidity opportunities (source: Alice und Bob on Twitter, May 28, 2025). Rollups, like those used in Ethereum Layer 2 solutions, bundle multiple transactions off-chain and submit proofs to the main chain, reducing fees and increasing throughput for token trading on primary networks (source: Alice und Bob on Twitter, May 28, 2025). For traders, parachains often allow exposure to emerging cross-chain assets, while rollups provide faster and cheaper transactions for popular tokens, directly impacting trading strategies and arbitrage opportunities.