Thanks GarthMJ for your answer.
If we want a clean installation for SCCM, I agree with you, but for SysAdmin point of view they will need do update 2 WSUS instances, the WSUS Server and SCCM Server with WSUS service included inside. The database in this both option will be always SQL Server.
So, GarthMJ what will be the issues if I just install WSUS feature in SCCM Server and then, on WSUS configuration, connect to that same SUSDB database already installed for WSUS server?
Thanks