You do if you have the only product that is doing the feature well.
But that doesn’t mean that file sharing isn’t like CDRW or Zip drives or small cameras.
After being a keen user for years I uninstalled Dropbox from my computer last week. It’s been replaced by iCloud, S3, google docs and other things that are easier for me to use in my workflow.
Mainly for sharing files via http and distributing/testing html/webapps when needed.
I used to use an app to mount s3 as a filesystem but tend to use command line to upload
In recent years Apple itself has started purchasing a ton of cloud services, including Box, for its own employees.