What can I say, it's pretty, blooms a long time, can take quite a bit of shade, and is drought tolerant. What's not to like? Some older varieties are prone to powdery mildew but this one is supposedly mildew-resistant and so far has been that way in my garden (this is its second year).
This variety gets about 80 cm tall and wide, but bee balm also comes in many other colours and heights. Great plant for late summer colour.