There are three main reasons that any video team larger than two people should be using shared storage.
Number one backup, without shared storage backing up can happen. But let's be honest it rarely actually does happen. Without backup. you put the entire cost of a project and not to mention client expectations at risk!
Number two speed, if you have more than one editor it's because you need to put out more content. You can't keep up with that expectation if you're constantly messing around with storage.
Number three, actually finding stuff. If you organize your files through spreadsheet and drive sitting on a shelf, you're going to lose files you're going to lose projects. It's that simple you must centralize data if you want to be able to find it.