The purpose of surge protection is to protect electronic devices from power surges or transient voltage. Surge power or transient voltage is a drastic increase in voltage which is significantly higher than the designated level in a flow of electricity.
It is also worth noting that the mains voltage varies between different countries. For example, in the UK, the standard voltage is 230 volts. However, in the US, the standard voltage is 120 volts. Problems may occur if the voltage rises above this threshold. This is why electrical surge protection is utilised to help prevent these issues.