Way back in 2007 , Boundary Groups did not exist. Then came SCCM 2012 and changed the game. We were given a “more better” way of dictating our content servers. But Microsoft didn’t stop there.
With the release of 2012 R2 SP1 (or 2012 SP2, but whose counting), we got to see “Preferred management points” make its debut. And as if that wasn’t enough, Microsoft continued to make use of the Boundary Group as if this was their plan all along. As of 1702, Software Update Points can now be added to boundary groups, thus minimizing the need (maybe eliminating?) the need for a secondary site.
Here is a link to the Microsoft Docs (the new technet) page discussing boundaries: Boundary Groups
What are your thoughts on the future need for secondary sites?