How did this thread end up on the stat board?
It's pretty simple TS% is a damn good measure of scoring efficiency; not perfect but close and a perfect measure would just be a somewhat modified TS%.
TS% defines the value of Melo's scoring; if ppg is quantity TS% is quality. If you're scoring 30ppg on 50 TS% that 30ppg has little to negative value. It doesn't account for whatever defensive pressure it draws and the easy shots it generates for others but that will show up in team ortg and teammates TS%.
Basketball is a possession game. Breaking it down as much as possible:
1. The goal is to win
2. You win by outscoring your opponent
3. You outscore your opponent by getting more points which happens by getting more points out of each possession. TS% is a huuuuge part of how many points you're getting in each possession.
This is why a lot of stat heads aren't huge AI fans. If AI takes 50 possessions which result in 40 points for him, 10 points for teammates he assisted after turnovers, rebounds and TS% are taken into account. AI looks awesome because he's scored 40 points and dished 5 assists but that's 50 points on 50 possessions (an ortg of 100 which is just how many points it would be in 100 possessions.) The average ortg today is 107 so in 50 possessions rounding up so the average team has turned those 50 possessions into 54 points so they've won the game. 54>50 to finish off the obvious.
TS% is a huge part of how many possessions are turning into points.
edit: addressing the other concern about 3 pointers, say you make 33.3/100 3 pointers vs 50/100 2 pointers (identical point value, same amount of points in both possessions) there isn't an inherent possession difference there. You make the shot they get the ball out of bounds, you miss the shot and they get a defensive rebound they get the ball. There isn't any inherent possession difference. The 17 extra misses are a bit more likely to end up fast breaks because it's easier to fast break out of defensive rebounds than passing out of bounds (duh) but at the same time it gives you more chances at offensive rebounds without giving up point value. How it weighs out I don't know but purely in terms of measuring scoring value TS% is still doing it's job.