It's kind of like screwdrivers -- for 99% of the people 2 would be all you'd ever need -- a medium sized phiilips head and a medium sized flat. But most people (speaking for myself) have a wide range of screwdrivers from very tiny to very large and of different handle materials... a bunch of very similar ones that wind up being duplicative , yes, but not exactly the same and never excessive.
It's only excessive if you have any custom made screw drivers or one with a pre-ban ivory handle.