Why the Thunder do it
The Thunder get even more draft assets to help build for the future and salary cap relief that doesn't send them into the lottery if they insist on continuing to be competitive. THJ's contract is also up just in time for the Giannis lead 2021 free agency class.
They add the following players to their roster:
Cory Joseph ($12.0M, 3yrs remaining)
Tim Hardaway Jr. ($20.2M, 2yrs remaining)
They add the following draft picks to their assets:
2020 - Round 1
2020 - Round 2
2020 - Round 2
Why the Kings do it
The Kings get some return for Bogdan Bogdanovic who they could very easily lose in free agency considering the other top players they need to resign and how scarce trades are for wings at this point. They also remain competitive and can still contend in the bottom half of the west well not spending much more money in the short term and having more cap room in the future. Plus that top 3 second round pick.
They add the following players to their roster:
Dennis Schröder ($15.5M, 2yrs remaining)
Dwight Powell ($10.2M, 4yrs remaining)
They add the following draft picks to their assets:
2020 - Round 2
Why the Mavericks do it
The Mavericks cash in their remaining assets to try and contend right now and over the next few years. The attraction of Luka and KP can intrigue the others to resign and their remaining roster is set for the next 3-4 years mostly.
They add the following players to their roster:
Danilo Gallinari ($22.6M, 1yrs remaining)
Bogdan Bogdanovic ($8.5M, 2yrs remaining)
They add the following draft picks to their assets:
2020 - Round 1