It’s true that at the core, the plutus and marlowe programming languages are meant to structure smart financial contracts, but the capability of cardano to plug-in to other platforms (interoperability) will make it possible and practical to open the ecosystem to almost everything, and at the same time keeping things secure because of the orientation and limitations of the Plutus code.
I think the applications are truly endless, but keep in mind that it would be the contribution of the community what will make Cardano, or any blockchain, great at the end. Just as Android will be bare lame with no apps, Cardano will be almost useless without really creative and well made dApps. Maybe in the future cardano will host services so complex such as Uber or Airbnb, where people will collaborate and bring resources together, who knows, maybe we can host the whole political and legal system of countries inside the most reliable, efficient and secure blockchain there is.
Fingers crossed!
I am from Mexico, so… Saludos!