Being incumbent in a space doesn't mean you do a great job at something. Whether this makes Talko interesting and useful remains to be seen (I'm reserving excitement personally), but I definitely think there's a lot of room for improvement that Talko is taking advantage of.
I recall Pogue's article on walkie-talkie apps (http://www.nytimes.com/2012/09/06/technology/personaltech/ze...), and how even the best apps had the most god-forsaken interface design.
Being incumbent in a space doesn't mean you do a great job at something. Whether this makes Talko interesting and useful remains to be seen (I'm reserving excitement personally), but I definitely think there's a lot of room for improvement that Talko is taking advantage of.