Why have macro position on cameras

I am using a Panasonic TZ15 and like most P&S cameras it has a macro position on the rear wheel.  I have decided to leave this permanently in the macro position so it is always ready for use.  From reading reviews I believe the macro mode allows for close focusing without affecting normal use and so far I have found this to be right.

If this is correct why do the camera makers bother with a separate macro mode, why not set the lens to close focus  and use the space on the rear dial for another function.

I feel there should be an obvious answer to this but I can't find one.