It did fill a gap for a while unmet by a lot of services that we take for granted now. A Mac Mini with macOS Server to host email, calendar sharing, file sharing, and Time Machine backups went a long way towards meeting a small office's IT needs. It's mostly supplanted by things like Google Workspace, Office 365, Dropbox, and proper MDM solutions these days, but wasn't a bad choice up through maybe 2014 depending on the situation.