Push-to-talk does not work well on in the browser at least on Wayland/Linux. The shortcut only gets sent to the active window, which for the type of contexts where push-to-talk is useful (e.g. gaming) is a dealbreaker. I've read stuff indicating that xdotool can manually handle things reasonably enough on X11, but I was never able to get it working reliably for any of the various Wayland replacements for xdotool, so when I've done voice calls, I've had to grudgingly use the desktop client.