Everyone has their own taste preferences and their own style of brewing. As long as you personally like it, it’s all good. But for anyone who cares a bit more about the flavor of their tea and wants to drink a consistent brew... the microwave is not. your. friend.
These rules are the foundation to brewing tea when you prefer not to use exact metrics and don’t need to be picky. It’s about using the least amount effort possible to yield an awesome cup of tea. This means avoiding bitterness, under extraction, and over extraction.