Pack indexing looks awesome, until now we had to do with TMP tricks to get the n-th element of a parameter pack (see this talk by Kris Jusiak: https://www.youtube.com/watch?v=LfOh0DwTP00 ). This could make the compilation of code heavily using std::tuple a bit faster (if the STL devs rewrite it to exploit that feature when C++26 is available instead of emulating it).