Gameplay isnt the most important thing in games.

[Smeags]

At the end of the day, games are games because the individual(s) ability to interact with the medium.

You mention the end result, which is the feedback that the player receives from the game in question (Whether it be happy, surprised, afraid, disgusted, angry, sad, etc.), but you also mention that what sets games apart from the rest is its interactivity. But interactivity and gameplay are one in the same. Gameplay is described as "the specific way in which players interact with the game".

Without gameplay, there is no game. It is a core foundation on which games are created, and therefore many people see it as one of (if not the most) integral functions that a game should be judged by. A game can exist without a story, or music, and any number of things that we see now-a-days. But a game cannot exist without gameplay. That is why so many people (including myself) prize games on how the player interacts within the game world.

So I'm not necessarily disagreeing with you, but just highlighting why many people prize gameplay over all else.