What is wrong with printed lyric sheets in the studio?
Paper needs light, a free hand and a page turn, and it rustles into a condenser microphone at exactly the wrong moment. A screen driven by the DAW timeline removes all three problems and keeps the singer's head up and on axis for the whole take.
The obvious win is time — roughly a quarter of an hour per song, which across a working week is most of an afternoon. The less obvious win is the tone of the vocal, because the singer stops looking down.
Rehearsal also transfers properly. A run-through with the prompter behaves identically at the take, since both are driven by the same timeline rather than by whoever is holding the paper.
No card required. Install the VST3, paste a lyric sheet, and record one take end to end before you decide.
Give them one rehearsal pass with the prompter set slightly ahead of the beat. The preference is usually for lyrics they can trust, not for paper itself.
Of course, and plenty of studios do for the first few sessions. It tends to stay in the drawer after that.