@miluo I can see that someone might believe that forums is like for the 1998 to the 2004 area. But those are easily proven wrong with the advancements of Bootstrap, Font awesome and other development tools. These tools are designed with mobile in mind and if you take a look at NobeBB and this topic on mobile. You can see how all the lines blend together. Taking this in mind a App developer can simply embed the forums into the app he/she is developing.
About the fact that the user experience is better on mobile, it somewhat is. Apps are build to work offline while the forums communicate online. Like you said in your previous posts Apps have all there data stored locally, and the only thing that they do is communicate with the servers to;
- See if any new chats have arrived
- Send a chat message if required
While everything on a forum is stored on there server and the data has to be fetched every time a user logs in with a considerable amount of time between it. This means that it is slower, by 1 second with a reasonable connection. This can impact user experience. The tradeoff for a slower connection is still that a forum still holds all the data and the data cannot be lost by user error.