Forward error correction (FEC) is beneficial in IPsec VPNs for several reasons. First, FEC improves the reliability of noisy links by correcting errors that occur during transmission, which ensures data integrity even in less ideal network conditions. Second, FEC transmits parity packets that can be utilized to reconstruct lost packets. This means that even if some packets are lost during transmission, the original data can still be recovered using the parity information, thus enhancing the overall robustness and reliability of the communication.