In the newest HUD update, the mic icon for desktop was changed. Seemingly, it was reimplemented from scratch, as there are big discrepancies. Specifically in this post, the mic icon now lights up or dims based on whether your mic is picking up audio. Which can be really distracting. (Even if you set your mic settings to "always off")

I just believe it's visual clutter when you intentionally have your mic off, and if I'm not mistaken though I'd have to double check, it's inconsistent with how the mic icon works in VR too. Though, maybe some people would still like it as an option.