Spurs get KD and trade back for Kon Kunepple spot. They weren't going to be able to play Fox, Vessel, Castle and Harper in that backcourt anyways. So, it's better to get value out of the pick and trade back for Kon. Having an excess of wings is more valuable in today's NBA than an excess of guards.

Wizards get their lead guard of the future in Dylan Harper in Exhange they give up the swap rights on the Sun's pick. The suns pick wasn't super valuable to them in the first place, so it makes sense to move it if it means getting Dylan Harper.

Suns get some depth and a sort of promising piece in Jeremy Sochan, as well as the 14th pick in the draft. They also get insurance (their pick) for next year in case something goes wrong like Devin Booker getting injured. If they want to go the route of trading Booker (preferably to the Rockets to get their other picks back) this also makes sense because they have the right to tank in 2026 and have more young assets. Rather than if they traded them to the Knicks for OG and depth.