He chose to use a service, something that contains software but is significantly more. He used a SaaS offering. That's not exactly unique, there's quite a movement towards using services instead of software.
I'm going to use an hour later today on using a SaaS which is basically open source hosted by the maintainers. Anyone can self-host that, hardly anyone does, because… because… I wish the presentation would go into those issues instead of rehashing the lost fights of the nineties.
Word processing is hard and a lot of work. Better to improve existing solutions and maybe bring them to the browser as a service.