Powder Efficiency or Powder Effectiveness: An Extreme Reloading Special Edition (ep.07)

When choosing a powder, should you use powder efficiency or are you better off using powder effectiveness? What's the difference? This video explains both as well as the ROI approach as well.

Links:
Extreme Reloading playlist (all) https://www.youtube.com/watch?v=mHru4dqrk6U&list=PL_KBTsQIm0U7y0L63duutM4vmKIXyu53k
Extreme Reloading playlist (Season 11) https://www.youtube.com/playlist?list=PL_KBTsQIm0U54NYSdBqjMVrvXD5kVW4ra