I use somewhat similar formula in one project to create a common baseline font size that 1) does not break with viewport size changes 2) remain legible for baseline user 3) gives good base value to scale UI elements by rem/em units.
Of course it's also a project where the user does not have a chance to mess with font size anyway for the main user, but I'd reuse the formula elsewhere.
Wish I could query the browser if the user has specific preferences, just like with "Dark mode"