system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why is blood pressure not measured in psi?
gpt
Before digital blood pressure measurement tools became widely available, the device used to measure blood pressure would literally consist of a column of mercury, and the pressure would just be the height of that column (millimeters of mercury = mm Hg).

Obviously now it can be anything but healthcare workers are very familiar with what normal values are in mm Hg so it's easier to ask the computer to do the math rather than have people doing unit conversions in their head.