Traveling, traversing meeting rooms. Going on site. There are lots of reasons battery life is important in the corporate world without being present in front of your computer for more than six hours consistently.
Then the corporate world has a solution for that for as long as computer existed: there's charging cables in basically every meeting room, every guest desk etc. In the olden days people would also keep around secundary, tertiary batteries to make the day. This would translate to a mobile battery in this days and age.
It's always nicer to not have to rely too heavily on these, but if your job is to be on the go all day long, you can't solely rely on your device battery either way.