Maybe it already has one? A super subtle one that I'm missing?
I know I really appreciate the messaging in Mountain Scaling, the bonus Qurazy in Cloud Rings, the chime in Abyssal whatever.
Obviously this is totally an OCD request on my part but if you have any lag while zipping through these it's not 100% clear that you've collected a coin you passed over or missed it and the completeness indicators (don't know what to call them) really are helpful and nice to have.