It would be risky. I think Arizona did it because Murray was going to miss half the season, thus making it a wasted season, so why not trade down and stockpile picks. Detroit did it because they were targeting Gibbs with their 1st pick and figured no one would take him in the top-half of the 1st round (they were probably sweating-it-out when Atlanta took Robinson 8th overall). Meanwhile the Falcons are there at 8 to trade down for a team looking for a WR while Chicago would love to take one at 9 to pair with Williams.
I would agree if both teams didn't need WRs for their franchise QBs.
It will be interesting to see how it turns out. I don't think McCarthy will be any good, much less merit giving-up extra picks.