It's like ya'll actively try to miss the point...
My point is simply a player that's -already- on the team and has a full year of SEC D1 conditioning & practice on the court is a more valuable scholarship holder than yet another big, post player (like Kent, Burns, & Walker) who is an unknown. Cardwell is rated lower than Olivier, he hasn't played in over a year and we don't even have an open scholarship for this class (at the moment).
Uros, Fulky, Pons, Olivier, Walker (incoming) with more time in S&C programming, another off-season of practice and film study are going to improve. With how the 2021 class is shaping up and potentially being in on far superior post talent I'd rather not kick Pember off the team to make room for Cardwell who we have no idea if he'd even survive Barnes' "fat camp" cause there's no doubt he'll be well behind the 8-ball having not even played this season of HS ball.
Now if a scholarship opens up naturally (Jalen Johnson grad transferring or foregoing his 5th season) then as BTO said, would rather get a more proven post in the grad transfer pool.