The Meteor semantic:ui package (and SUI in general) will always continue to get updates. However, I do believe the approach of maintaining a custom local package w/ the SUI code in it is superior to using the default Meteor package. But configuring things in this way is much more complicated than just doing meteor add semantic:ui.
I would take it as good news 
It is the strongest possible evidence that Meteor can work extremely well w/ Semantic UI!