Prospects that are traded for rentals can turn out to be very good. In August of 1987 the Braves traded Doyle Alexander to the Tigers for a young pitcher in AA by the name of John Smoltz.
The Rangers have to be thrilled with how the Monty/Stratton for Roby/Saggese/King trade worked for them in 2023 but it could turn out to be a good trade for the Cardinals in the long run.