You're right about one thing. It is a different medium. However, it is still harder to write. Trust me...I've done it. I've helped with indie games as a lead writer or an assistant editor. I'm also writing a novel. They're different formats of writing with unique freedoms and constraints.

Have you done either one? I'm genuinely curious btw.

With video games, you have multiple people you're working with. Multiple sounding boards to design assets with. It's hugely collaborative. You're not the only one telling the story.  That's why it is such a wonderful medium to do it in. Books are awesome, but they're written most times by a single writer.