Is there any reason to buy the iWork bundle instead of the apps separately from the App Store? Keynote is $19, Pages is $19, Numbers is $19. iWork bundle is $79.

Why would anyone want to buy the bundle?
I guess it's mostly here for people on Leopard and older version of Mac OS X. Since the Mac App Store only works in Snow Leopard and later.

It could also be for people who don't want to depend on an internet connection when they need to (re)install, and want to have the app physically at all time.