There are two broad types of meditation: concentration, and reflection. I can see how e.g. video games could be a kind of concentration practice. The benefit of deliberate meditation concentration practice is that you learn to apply concentration in non-stimulating circumstances (or rather, you learn that you don't need graphics, meaningful choices, tight timing, or points to stimulate your alertness). Most beginner meditation falls under concentration (brain-settling) practices.

Then there is the reflection/insight practice, in which your mind pays deliberate attention to its own internal machinations. With the right touch--neither too tight, nor too loose--you can maintain an appropriate distance so that you can see what's going on, but not get pulled under. I find it difficult to believe that any activity other than mental reflection, no matter how focused, would be an effective substitute.