But does that justify the higher price? If there is not much difference in performance, it seems most obviously not.Careful. Some high power tools REQUIRE the high power batteries to work. So there IS a difference.
Standard tools have a + and - on either side of the battery. HP packs and tools use ANOTHER set of contacts in the front (?) of the battery. So when you look inside the battery well you see 3 contacts instead of 2. To my knowledge, there are VERY few HP tools.
EDIT: since the extra contacts are only to provide more current to the tool, a HP battery in a standard tool will perform more or less equal to a standard battery.