They did him a solid. I'm sure the development staff and coaching staff talked it over with management, and they felt he wasn't going to make the team with all the new acquisitions they got over the summer, i.e. Heinen, Sherwood, DeBrusk, etc. He'd now have to go through waivers to be sent to the AHL, so they'd be lost for nothing should they not make the team.
Could argue that they could have kept Podz over Sprong or something, but they were looking for something specific out of Sprong that Podz wasn't offering. Podz had plenty of opportunity to succeed here, and he didn't seize it.
Why they did him a solid, is that they could have run Podz through camp and then cut him and sent him through waivers, leaving him to be picked up by awful teams in god knows where. Instead, they trade him to a rival within Canada, a short flight away to Edmonton, causing minimal impact on his family. It also so happens Edmonton was absolutely starving for a young, cheap hardworking winger, and probably the best opportunity for Podz to get a footing in the NHL on a top team. And look what has happened, he's playing with Draisaitl and doing well, and will probably have an NHL career now. If they didn't like him as a person, there is no chance they trade him to a rival.