Redundant words in sentences

Below are sentences taken from two model answers to an English test paper published by an English daily.

All in all, this novel has provided useful lessons for the benefit of readers.

One will see that if the words in bold are taken away, the meaning to the sentence will remain the same - All in all, this novel has provided useful lessons for readers.

From another model answer:

Bravery is shown when Robinson Crusoe fights and gets rid of the cannibals that comes to the island. He is indeed brave when he fought the cannibals to ensure his own safety.

One will realise that the singular verb 'comes' should be replaced by its plural equivalent and that there will be no change in meaning if the two sentences are combined into one with the words in bold left out: Bravery is shown when Robinson Crusoe fights and gets rid of the cannibals that come to the island to ensure his own safety.