I'm talking about an instant hot water dispenser which can put out 210°F or 99°C almost instantly.

You have three main ways to heat water for something like tea.

1 Boil on stove top

2 Electric Kettle

2.5 Electric Kettle with larger tank and dispenser (Zojirushi)

3 Instant hot water faucet with heater tank under cabinet

*Microwaving water can be very dangerous

My opinion is while opinion 3 is the most costly, it is super nice and convenient if you use it often.