A water kettle lets you consistently heat water to the same temperature (not just boiling, high-end kettles have additional temperature options), regardless of:
Well our kettle is 2.4kW, our microwave is 800W or so effectively. Also our induction stovetop is much faster, so the nuking option is slowest by a lot.
- Amount of water
- Initial temperature of water
- Position of water container
They also prevent superheated water accidents.