There is a lot of tooling around Office that would require a Windows server. Some games require it as well for hosting. Also many corporate networks use MSSQL s

There is a lot of tooling around Office that would require a Windows server. Some games require it as well for hosting. Also many corporate networks use MSSQL server, Active Directory domain controllers, etc.... Wouldn't choose it as a server if my applications doesn't require it, but I guess there are still a lot of cases.