Your imagination is very limited. SMTs can be used for way more things than the uselessness we've seen with HIVE engine.
Creating a coin with an inflation and designing the right sinks to burn it, in a game for example, will provide great usecases. Or even just use inflation and back the token with half of the app revenue.
It allows developers to ICO their own token for their own platform and for their own specific purpose, tweaked with inflation rates and special sinks.
Not everyone wants to integrate HIVE. HIVE is the RC token.