volt stabiliser avoids any electrical damages in the case of current or voltage instability. It is the same as any electrical devices that you have at home. Some people use volt stabiliser to avoid their electrical devices such as computers, plasma TV from being damaged internally from the short circuit or from voltage instability.
Volt instability is definitely one of many sources that damages electrical devices.

Also, changing your battery to dry battery will also help reduce the likely chance of voltage instability

hope that helps