Not every change is based on stylistic fads alone. Rounded corners on elements can increase the ability of users to recognize them and separate them from other elements, because visually the borders are less likely to be confused with other UI elements (lower cognitive load).
This article quotes a researcher on this topic:
> A rectangle with sharp edges takes indeed a little bit more cognitive visible effort than for example an ellipse of the same size. Our ‘fovea-eye’ is even faster in recording a circle. Edges involve additional neuronal image tools. The process is therefore slowed down.¹
And they still managed to get the round corners wrong, apparently. According to that page, the radius values are hardcoded in pixels, so they don't scale with the display's DPI setting.
That's at least a decade after the W3C had a well-developed concept of relative units for use with the CSS:
Thus, with a sufficiently high DPI display, you're going to miss out on one of Windows 11's "signature experiences" and end up with "legacy" squarish corners instead.
They use "effective pixels", just like CSS pixels are not actual pixels:
> Because of how the scaling system works, when you design your UWP app, you're designing in effective pixels, not actual physical pixels. Effective pixels (epx) are a virtual unit of measurement, and they're used to express layout dimensions and spacing, independent of screen density. (In our guidelines, epx, ep, and px are used interchangeably.)
I just updated to Android 12 and the new border-radius on nearly every UI element is beyond absurd. It actually looks like someone just discovered that CSS property, and instead of being told by a designer "that looks goofy and childlike, tone it down," they doubled the value and put it on even more elements.
My notifications pull-down fits about 3 useful notifications. The rest is whitespace and rounded corners 4 layers deep. It's horrible.
Pill-shaped buttons were part of the Aqua theme in the original release of OS X. For a long time after that, UIs aped Aqua with pinstripes and jelly-shaded pills and while the pinstripes and jelly have gone, I think the pills are here to stay for some styles.
Yeah but there was a huge push just last year, basically every single SaaS app to Firefox, everyone folded. During the Aqua days, every company had their own unique take on design. Today, it is a design monoculture driven by the types of Stripe and Apple.
Design used to be a differentiating feature. Everything looks the same today. Kind of a Big Tech dystopia, even in design.
