I am a big proponent of the First Rule of ARIA (don’t use ARIA). But ARIA brings a lot to the table that HTML does not, such as complex widgets and state information that HTML does not have natively.
A lot of that information can be hidden to the average developer unless they are checking the accessibility inspectors across browsers or testing with a suite of screen readers. This is one of the reasons I always advocate for making your styles lean on structure and attributes from the DOM, to make it easier to spot when something is amiss.
It is also, in my opinion, a way to reduce the surface area for accessibility bugs. If your sort icon orientation is keyed to the ARIA property that conveys that state programmatically, then getting that ARIA property wrong will have two effects — a broken interface and a weird icon. Addressing the accessibility issue will fix the visual style.
Source: Using CSS to Enforce Accessibility, an article by Adrian Roselli.