Those who care anyway already use clients which support OTR with the same Google Talk or any other XMPP server like Pidgin, Adium, Jitsi and etc. Those who don't care won't use anything even within the Google Talk web application.
Standalone XMPP clients anyway are way better than Google Talk web application, since they are more flexible and allow using several accounts at once.
Standalone XMPP clients anyway are way better than Google Talk web application, since they are more flexible and allow using several accounts at once.