Why each team does it -

Cleveland - They now have an absolutely loaded frontcourt with the addition of Allen. Getting whatever they can for Drummond before the trade deadline is smart. Give Allen and Nance more time to work together on the court.

Charlotte - Charlotte has a chance to be a playoff team this year, and while Rozier is a good scorer, LaMelo has proven to be an potential star as a rookie and this move will put him in the starting Lineup. Drummond would give them an immense boost at both rebounding and interior D, PJ at the 4, Hayward at the 3, Melo at the 2 (size reasons, he will obviously run the offense), and Graham at the 1, if Hayward stays healthy they could be a Eastern Conference Semi-Finalist.

Knicks - I think the Knicks need some help beside Barrett and Randle, Rozier provides a punch that their other guards just don't have. Giving up a late first and the much maligned Smith wouldn't be that much and he could really give them a push, possible 8th seed?