I don't think ATMs appeared equally early everywhere, but in any case, 'killer app' in this context points to the fact that the Visical application made busines

I don't think ATMs appeared equally early everywhere, but in any case, 'killer app' in this context points to the fact that the Visical application made businesses go out and buy Apple II computers, just so they could run Visicalc. They didn't, before Visicalc. That little piece of software made the sales of Apple II explode and laid the fundament for having something like the IBM PC in the office. ATMs were very useful for people, but it didn't create a fundamental change in the use of computers.