“What is a video game” is one of those questions that will drive you to madness partially because video games are kind of more of a medium than a specific art form but also because there’s a certain amount of subjective “you know it when you see it” aspect to it. A fitbit obviously isn’t a video game, it’s a device that gameifies exercise.
Ultimately you just have to draw an arbitrary line somewhere. In case you were wondering, for me a visual novel is a video game but a kinetic novel (visual novel with no choices) isn’t, so the line is in there somewhere