The full trade is the following

Celtics In: Draymond Green, Walker Kessler Out: Kristaps Porzingis, 5 2nds

The Celtics do this for the future. They trade an injury prone Kristaps Porzingis and 5 end of the draft picks for Walker Kessler, who, after signing a extension, will be under contract for 4 years and 50 million. They also get back Draymond Green, who will help them add depth to the wing and will expire just before Kessler's contract kicks in. This is a play for the future, as the Celtics don't sacrifice too much right now for a much longer championship window with a core of 28 year old Brown, 26 year old Tatum, and a 23 year old Kessler.

Jazz In: Kuminga, 3 2nds Out: Kessler

This trade is a upside move for the Jazz, as even though Kuminga is going to get his extension a year sooner, his upside is All-Star while Kessler probably won't be anything more than a solid starter. If Danny Ainge needs convincing, the 3 2nds, despite being the worst picks possible, may help convince him. They also sign Kuminga to a 60 million contract extension that will carry them through 4 more years

Warriors In: Porzingis, 2 2nds Out: Green, Kuminga

The is the ultimate win now move for the Warriors. They sadly part ways with Green, which may be a sticking point, and Kuminga, who is their best young piece. However, if they don't win a championship this year, they may make a big swing to try to capitalize on Curry's final years. This is that. The 2nds are also not the most intriguing asset, but they may help nonetheless.

This is obviously assuming the Warriors don't win a championship this year, that the Celtics either flop in the playoffs or do it without KP again, and that neither Kessler or Kuminga is able to demand a much larger extension.

Who says no?