Semantics. The end result is the same: there is almost always a large amount of spare CPU cycles on each physical box, which can be utilized by instances to "burst" above their allocated capacity.
It's more than semantics. The term "burst" carries the implication that you only get something for a short time. That's really not a good reflection of reality in this situation.
Words have meanings and carry implications. By your logic, we might as well use the term "banana" instead. The point is that the concept doesn't reflect reality, and thus your point has no merit.
