Reason why each team says yes
Raptors: While losing an all-star in VanVleet, high level player in Siakam would hurt. The Upside for Toronto is insane. The starting lineup would be the best defensive lineup in the NBA. Simmons, an elite all around defender. Trent Jr, a perimeter defender with an eye for steals. Anunoby, an all around defender who can score. Barnes, a talented rookie who is still learning the ropes but showing signs getting near a steal and block a game. And Turner, the 2nd best rim protector only behind Gobert. Turner will allow more spacing for a team who has lacked all season. Simmons also finds the perfect role has Toronto would need his defense and playmaking, not scoring. you can leave that to the other 4 starters who are avenging 14.5 or more to the exception of Turner.
Pacers: while they want to blow it all up this gives them 1 more chance to see what happens. the worst case is Harris builds up his value again. Sabonis moves to center where he should be playing. if he ends up being an efficient center more teams will call in the offseason. the more bidders you have the better offer you'll get. they also bring in 2 young players and a draft pick. if a Harris Sabonis pacers team starts to win they'll have some assets to aquire another player. oh and if they save there money this offseason thanks to Sabonis being underpaid they'll have the money to bring in a top tier player
76'ers: Is it the Beal or Lillard they wanted no, but it is an allstar point guard who is making the second most 3's a game only behind Curry. Siakam who might've proven he can't be the main guy can be the 3rd on a championship team, he's done it before. Levert brings scoring either off the bench or starting depending how they feel about Green or Maxy playing the 2/3. regardless they turn a non factor in Simmons to an all-star point guard and 2 other starting level players.