One important stage of error correction is spreading, that use a pseudo-random function to 'spread' the damaged data over several blocks that can be then completely recovered, instead of concentrating the damage in a single block (like often happen in erasures) that cannot be recovered.
Optical media like CDs and DVDs use a similar interleaving scheme, allowing for large amounts of errors to be corrected; in fact, even during normal operation with what appears to be a completely clean and perfect disc and drive, read errors are always occurring but corrected silently so there is no loss of data:
Pseudo-random scrambling is used in places like https://en.wikipedia.org/wiki/64b/66b_encoding to reduce the chances of many consecutive 0s or 1s which could cause clock desynchronization between the sender and receiver.
