The answer is actually pretty simple, imho: if your app doesn't require MeeGo's capabilities, you don't differentiate. Despite Qt being awesome, Symbian will never be a Unix-like operating system. End users will just see that cheaper phones don't run as much stuff as more expensive phones.
Qt only needs to be pushed to developers. Right now, it can even be promoted to users, but when there's enough software, they won't need any convincing about developers being present.