it sounds odd to trade for another FRP, when the draft is allegedly weak. on the other hand, this is the reason why the picks might be available at a reasonable price.
let's assume either 21, 22, 24 might be available for SRPs.
the appeal of a pick in that region is, that it might work as a tailhook for that player who, for whatever reason, falls out of the lottery. that's where you luck into the Tyrese Maxey's of the draft.
that guy might be Walter in this draft. or Topic. even Dillingham. Carrington. Carter, da Silva, Knecht, because of their age. the list is not complete. lot's of scenarios come to mind.
and if there isn't this steal, you can still trade the pick, some team will call during the five minutes.