Unfortunately, you can't just put plants everywhere. CO2 conversion is also highly dependent on light levels, which sufficient light levels not being achievable everywhere.

Office buildings with a large number of people meeting rooms etc.) could also benefit from monitoring.

Heck, even at home, I have a room that quickly accumulates CO2, easily reaching 2000ppm with just a single person being inside, which makes spending prolonged time in said room a tiring affair.

https://pmc.ncbi.nlm.nih.gov/articles/PMC11253968/

https://www.pjoes.com/pdf-68875-24089?filename=The+Influence+of+House.pdf

https://www.sciencedirect.com/science/article/pii/S2666790823000502