Compare it to gattling guns GAU-8. They shoot at 3900 rpm but only for a few seconds. The reason is that a firing solution may only be correct for a split second. It's all about peak performance because you only shoot when you really need to.

The same thing happens with these large instances. Because these instances are so much bigger that you won't use them for the entire month. You'll use them to get results within hours or days.