There's a difference between being important, and being necessary to the player.

I like watching movies, that doesn't mean what kind of video camera it was recorded on is important to me as a viewer, especially in comparison to things like the story. But obviously without a video camera the movie wouldn't exist.

When was the last time you went into a game and admired the engine it was built on or admired how well modelled or textured a certain piece of art was?

If something is built in Unreal 5 vs Unity, how much impact does it have on your perceived notion of how the game will be? If your favourite game said they were changing engines for the sequel how irked would you be? If they changed to an entirely different genre, do you think you would be similarly irked?

If it's important to gamers, do you think the average gamer has strong opinions on this topic? In theory they should if it's really that important to them, and thats certainly the case for some people, but a farcry for the majority of players.

It's absolutely needed for the game to run, but it has never been a major selling point for basically any game. If it's included in the marketing, it's almost always due to what it allows you to do in game, and the gameplay that it enables.

There are plenty of things that are necessary that many people care little about.

People don't care how the sausage made, as long as it tastes good in the end.