From what I’ve read, it seems to be a preference. Most things with Tea are. Perhaps you follow the instructions precisely, but you like your tea stronger. You might add more than instructed. The best thing to do is find a method that works for you and be consistent. A lot of people measure in Teaspoons, so that might be a little easier. However there are quite a few drinkers and tasters who measure by weight.
Why not try both and see which works best for you? I tried weighing my tea when I noticed that’s how Rishi does it’s tastings. However, I went back to teaspoons when I noticed almost every label is measured in teaspoons. However, Tea for Me Please is a great blog and the reviews are done by weight. Like I said, a matter of preference. 🙂