Stopped reading when the author suggested caring about chrome and safari but then said “who cares about it (Firefox) anymore”.

I prefer round[ed].

Think of it as a rounded square with a unique, pleasant shape.

I don't find them pleasant. I find them irritating.

Rounded square makes use of the space it reserves/square-fills. Squircles seem wasteful and confusing. They do not represent any common physical shapes, and waste/discard space they could use. They look like an old CRT.

Lost me when it started talking about discontinuity of curvature as if that's something that's important. It's important when building a railway, but not when drawing something squarish. I'm gonna complain that squircles aren't third-differentiable.