Memphis is awesome, but they don't have a tall/long wing stopper. Grant is a great, switchable, two-way wing with playoff experience. He scores at all three levels and can get his own shot. A Grant + JJJ frontcourt has ridiculous defensive potential. Or they go huge with Grant, JJJ, and Adams on the court. Give Grant the kind of spacing and point guard play he would have in Memphis, and he would look that much better. Trey Lyles adds another capable stretch 4/ spot 5.
Memphis declined Culver's 4th year option, so he is a throw in. Kyle Anderson is there as salary. Memphis also has 3 1st round picks, each likely to be in the 20-30 rangE, they give one to Detroit. The prize for the Pistons is Ziaire Williams.
This trade gives Memphis a two-way 20ppg wing who is as capable at checking the elite wings of the NBA as anyone, while still leaving enough assets to make another move if they want.