Nokia’s legendary font makes for a great user interface font

UI has some very particular requirements—typefaces have to be hinted really well so that they work on displays with lower pixel density. Also, such typefaces generally have very tall x-heights so characters can be distinguished well, which can be seen in all the early 2000s UI typefaces, from this Nokia one to Lucida Grande, to Tahoma. More modern ones tone this down a little, at the cost of some character. SF Pro, Segoe UI and as the user mentioned, Inter are considerably closer to Frutiger and Helvetica.

Speaking of which...

> finally displacing Inter after many years of uncontested service

Inter is by far the blandest typeface possible—it feels like the designer thought 'let's take all the sans-serifs and smush them together'. Its several contextual alternates just dilute it even more. I would never use it for UI, let alone any sort of branding.

I like Inter mainly because it’s one of the handful that renders in a way that looks “right” to my eye regardless of platform. It’s bland, but incredibly consistent.

Lucida Grande is very nice for example but clearly designed for the OS X and iOS text rendering systems of its era and looks odd under Linux. Similarly MS UI fonts look weird in the absence of ClearType.