To start ino he has a bad contract but that's kind of the beauty of it, his trade value should be low still despite improving recently.
Some may think this is a overpay but we know what Utah are like and for me tims contract isnt great either, Omax doesn't play yet and Powell is terrible.
Dallas get size and rebounding, defence and a really good 5 for when livelys resting,pick and roll and so on. He also can play the 4 well when livelys playing as long as he has a good season from 3. 34% this season with a career low of 27 and high of 40. Risks are clear he could shoot badly and end up as a backup 5 for 25 million for 3 years.
Utah get a good prospect, a decent player in THJ and with a shorter contract than Collins and a easily flippable contract in powell and a first.