Sometimes it’s just to gauge how things change over time.

If you said 5 when you came in, but 3 after an hour, then we can make decisions based on what happened between those times.

If you said 3 when you came in but now it’s a 7, maybe there’s some emergency that needs to be acted on now.

If you said 9, and that makes sense based on what is going on, you get some nice drugs for a bit.