My experience using Clip Studio Paint's 3D reference models extensively has been more positive than I expected when I started.

The models I use most: the default poseable figure for checking proportion and foreshortening, the hand model for specific hand positions (hand positions are my weakest anatomy), and the basic furniture and prop models for interior scenes.

The limitation I've run into: the models are useful for structure but can create stiffness in poses because they don't capture the organic compression and stretch of real bodies. I use them to check my poses rather than to source them — draw the pose gesture-first, then use the 3D model to verify the anatomy is plausible.

The workflow that works: pose the 3D model, take a reference screenshot, drop it onto a reference layer, draw over the key structural lines only, then delete the reference and continue painting from observation and imagination. The model confirms; it doesn't drive.