I use a Synology NAS at home and have installed mutli-office setups for customers using them.
They are very easy to use and very flexible.
You can access your files from anywhere you have internet (or mobile phone access if using their app) from pcs or macs.
I'd put these in wherever a customer just wants straightforward access to their files over a network or internet.
Much siimpler and cheaper than a server - no software license.
Mark