Have you ever wondered the same questions? Look at the following Control Panel window, do you know which font has been used?
Yes, it’s Segoe UI font at size 9 for normal text, like blue color ones in the picture.
According to Windows User Experience Interaction Guidelines, a 800+ pages free guideline from Microsoft.
Segoe UI is an approachable, open, and friendly typeface, and as a result has better readability than Tahoma, Microsoft Sans Serif, and Arial.
Segoe UI is optimized for ClearType, which is on by default in Windows. With ClearType enabled, Segoe UI is an elegant, readable font. Without ClearType enabled, Segoe UI is only marginally acceptable. This factor determines when you should use Segoe UI.
So yes, because of the population of LCD monitors and the wide-adopted ClearType on Windows, it seems no reason why you shouldn’t be using this Font. Indeed, it’s a Windows Font intended for user interface text strings.