Yes we don't manage all the BBCodes right now. Only the list shared above for the moment. And yes the work is in progress to manage all the popular BBcodes in the next weeks. Sorry I don't see the issue here and I said later:
Keep in mind that the app is still very young and needs improvements
Topic'it is not better than responsive websites and it's not the purpose of the App
... I told you it's an additional way
to browse, participate and follow forums. The idea is to offer members the most suitable solution for their use. If some mobile users prefer the app version and participate more on the forum thanks to Topic'it (via push for instance), what is the problem for the founder of the forum?
Some mobile users prefer the App version, others the responsive website. You can ask your community if they use the Facebook or Twitter mobile website or the app for instance. The goal is clearly not to replace the website. Just to propose an additional solution to the members.
Some members find the access to the forums easier than on a classic web browser. And maybe your members participe to several forums, not just your forum. If these forums are on Topic'it, he can follow, discuss, be alerted and stay connected on his forums in a single app.