Why the Knicks do it
Richardson gives you the same spacing without needing the ball as much. Can't score on the same level but Zhaire Smith is a promising player in the same timeline as the youth.
They add the following players to their roster:
Josh Richardson ($10.1M, 3yrs remaining)
Zhaire Smith ($3.5M, 4yrs remaining)
Why the 76ers do it
They have reported interest in Morris and the only way this happens includes Josh Richardson because of contract matching. Smith is outside of the rotation for the most part and the only piece NYK would want to again fit in their timeline.
They add the following players to their roster:
Marcus Morris ($15.0M, 1yrs remaining)