The article compares two Byzantine Fault Tolerant (BFT) consensus protocols, Practical Byzantine Fault Tolerance (PBFT) and BBCA-Chain, focusing on their approach to transaction processing and consensus. PBFT, a longstanding protocol for state machine replication, uses a sequential leader-based model that involves a three-phase process to achieve consensus, with a complex view-change regime to manage uncommitted proposals. In contrast, BBCA-Chain operates within a Directed Acyclic Graph (DAG) framework, enabling parallel proposals and leveraging a probing API to manage view changes with reduced latency and complexity. While BBCA-Chain offers higher throughput due to its parallel processing capabilities, it faces challenges with transaction duplication in shared mempools, which can complicate consensus in environments with constant transaction backlogs. The choice between sequential or parallel processing in these protocols depends on the application and system state management, with each approach offering distinct advantages in different scenarios.