The Timberwolves don't play all three of Rudy, Towns, & Reid at the same time, so adding Bruce would give them a Championship-caliber rotation option for the playoffs who can stay on the floor late in close games.
The Raptors clearly aren't looking for far-out draft capital, instead they're stockpiling young 20 year old players with promise (see return in OG deal). Reid fits that mold perfectly and would slot in great next to Barnes, Quickley, & Barrett going forward. (McLaughlin's salary could be replaced with anyone else on the back on the roster)