Why are timing belts used instead of chains?

Timing belts are expensive to replace, and my Golf needs one every four years. Do the manufacturers just fit them to create work for themselves or are there sound engineering reasons as to why some engines have belts instead of chains?
Belts are cheaper, quieter and easier to engineer, though some last longer than others. Pulleys, tensioners and waterpumps are more likely to fail and throw the belt off than the belt is to simply snap.
Answered by Honest John on

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