Well there is one, and you said it yourself "devs to work on it". It needs DEV time and really this is a super low priority at the moment...
It would makes more sense to me to have such an app ready for 2.0 release, when SE will be expecting new players and when these new players will need to secure their accounts. Also XIV isn't popular enough now for RMT/Hackers to target players with phishing website/keyloggers and all, in order to compromise their account and make profit (it's a business after all), so threat level is low, the need for a token is limited. Finally, current players most likely acquired a token if they wanted one.
Sure having an app on top of that would be more convenient etc. Then again, they are more important things to fix now, hence I hardly see anything coming before 2.0 hits.