I think you could have a reward system (like Stackoverflow but different) so yes, you could use such a coin for this.
Maybe something that a user recieves if their answers / questions recieve upvotes, or an answer accepting mechanism that dishes out coin. Users can spend these for special providleges like getting more eyes to their question.
Badges are another idea, on or off chain!
Maybe we can try something in the future. Currently I don't see much use. If we wait for SMTs, it would be better IMHO. There are only a very few projects like @leofinance that has done well with HIVE-Engine. First grow the project as is and by the time we get SMTs (which could take another year) we can look for a seperate crypto. No need to over comeplicate things from the begining.