@jv it depends. For example almost everyone I know who uses web chats that work with xmpp pipe it to their accessible desktop clients since the web ones tend to kinda suck. One exception apparently is IRCCloud. Whether a native app is accessible or not, just like the web, depends entirely on whether th developers bothered to try to follow the standards for whatever they were building for (there are standards for native controls and apps by each of the OSes)... that doesn't hit everything but when devs try, a lot ends up working.