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.
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