Of course this is a way of thinking about pitching the game to, say, a publisher. But you do not pitch a game to a player. You might advertise it, certainly. But you would not use all the same advertisement material in a pitch and vice versa.
Also, the scenario was a bit narrowed down to convince personal friends to play the game, and they responed with, oh yeah, you made a game with that topic, we already have big budget games with that topic, why should we play your's? (to paraphrase it). And than it got expanded, to literally, the question, why play racing game, when top racing game exists, why play city builder, when top city simulator exists, and so on.
It is pointless to compare what games offer in this direct confrontation. We all would only ever play big budget games, and only a handfull at that. And reality shows, that players do not select their games by this logic.
So I stand by my answers. "Because it is fun to play. That is why you should play my game. And because I made it, and you are my friend. And when you tried to cook that awful pizza, you made my try it too, and I did not ask, what does your pizza offer me, when there is a good pizza restaurant nearby."
And yeah, I do think there is a difference to whom and why you pitch your game. There is a reason why indie is indie. With the exception of small studios that still call themselves indie, just because they are small, all indie games are essentially games that were not pitched to a publisher to do the publishing. Either by choice or because, well, because while they might find their audience, they are not exactly pitchable material. Just look at rpg or visual novels, or, gasp, horror games. Everyone and their dog is making a fnaf clone. Rpgs are hero saves the world from big evil, visual novels are boy meets girl and so on.
But bottom line, the trivial and good answer to both, why should you play my game, and why should I even make that game should be: because it is fun. We do can play more than one game, even if they are the same genre and topic.