honestly, this feels like a great feature for today, especially with the prevalence of smartphones and the mobile web! now we have devices that are mostly easier to type/compose messages on and the fierce rush to build an app for everything has imo reduced the "cool factor" of a bespoke native app. i hate installing a new app to use a service if the app is buggy and the workflow could be done some other way (even responsive webapp). personally, i really enjoy sms based UX.