Earlier quoted context omitted.
Given differences in monitor pixel densities, OS zoom levels, and distance from eyes to monitor, comparing any point/em/etc measure is practically worthless. For example, I can use a 12pt font on my macbook pro's screen, but have to go up to 16pt on my 4k display at home, and down to 9 or 10pt on the 1920x1024 screens in the office. It's a pain, but... Instead, if you really want to compare font sizes, compare either…
I don't have a ruler handy, so here are two random screenshots I just made, showing terminal and Emacs font sizes I use, relative to my 1920x1080 laptop screen: https://i.imgur.com/dbijNop.png https://i.imgur.com/cS6EOhZ.png
Depending on your eyes that would be entirely reasonable on an 18 inch lapzilla or preposterously tiny on a 9 inch ultrabook.