The most common way to express the results of this equation are stating how much energy is locked in a paperclip or some other small object. This is pretty abstract though, because in practice one could never convert the entirety of a massive object into energy. That sort of thing mostly only happens with tiny fundamental particles.
One neat thing to keep in mind though is that it goes both ways. You can convert mass into energy, but energy can also turn into mass. An example of this is when you try to separate two quarks. The thing about quarks is that they’re never found alone, they can only be found paired up with other quarks. The forces binding them together are too strong. If you try and pull apart two quarks, the force between them stretches like a spring. That “spring” contains potential energy. If you stretch it enough, the energy materializes into two entirely new quarks to pair up with the first two you were trying to pull apart, leaving you back where you started.