Yeah this makes absolutely 0 sense for Chicago.
In two years, there would have been no way to re-sign Hammer or Breadman. Saad and Murphy are signed for 4 & 5 years, respectively. It seems Chicago's decided their $10 million Captain can't produce without a $5 million + wing, while their $10 million wing should still be able to produce with less expensive talent. And the anchor of a contract they gave Seabrook left them with only two high-priced guys who could be moved -- and they moved them. That's the pessimist in me.
The optimist says Saad for Panarin is a pretty even trade -- Panarin doesn't come close to Saad defensively, so on the 'Hawks, he has added value to close the offensive gap. And he's got an extra two years on his contract, he's younger, and Chicago got their cheap back-up goalie. (Motte helps even up the value for Columbus.) It also permits Toews to again match up with the other teams best line -- without Hossa, the Hawks top line didn't match up nearly as well, and maybe deBrincat can deliver goals in the NHL. But all that makes it about 2019-2020, when Toews/Keith/Seabrook will be worse players than they are now.
The Arizona deal is a bit of a headscratcher, but I don't know much about Murphy or Dauphin. It seemed Hjalmarsson was destined to be moved, and maybe at 30, getting younger and (slightly) cheaper, for three extra years, helps. Maybe the Hawks believed he was slipping a bit, but I'm not sure how much value they got back.