I suspect you haven't quite understood how this works.
Here's how Box works for me.
Logging on to Box, there is 2FA which means that cracking my password alone would not give access to the files.
I have the directory I work with synched with box, both on my laptop and desktop. This works in the background and updates two way changes between the cloud copy and any number of remote copies. That way, I work in the office, at home, whatever, as long as I had Internet access when I was last making any changes I'm working on the same
local files. If my laptop broke/got stolen (it's hard encrypted) I wouldn't miss a beat, moving to a new laptop/desktop is a matter of seconds and you have everything just as it was.
You can share a directory/file with a remote user by sending a link.
Not sure where this comes in the offerings, but we also have office online, that lets you work collaboratively and see changes in real time (much like google docs).
Box is not the only cloud offering, Google, Microsoft, others all do it but it is very much geared to business use.
The only reason not to use it or something like it for your office work is cost, if achieving the level of service you need costs too much. eg, if you need the data held in the EU (or even UK) I know Box will provide, but I don't know where it falls in their pricing, probably not for their basic £12/month (3 users @ £4), the £36/month might, I dunno.
ETA as suspected, it's from the £20/user/min 3 user=£60/month offering "Box Zones"
https://www.box.com/en-gb/zones if you need to have the location specified