Thanks for the comment @abh12345.

That is my understanding also; that SP will apply to those apps created using the SMT protocol. That would make sense since an app like that, even with another token, is still reading the same blockchain (similar to DTube etc...). Of course, the app can choose the percentage of reward and alter things like that but I think the basic system is in place for any token creator.

Perhaps, since every SMT created token is paired with STEEM, SP can be used since there is an instant conversion rate available. Have none of that token but 1000 SP, if it is a 3 for 1 swap on the exchange, it is like you have the VP of 3000 of that token. Just speculation on my part.