Not all movies are good in the same way.
70MM IMAX provides a stunning picture that can't be equaled. The screen is gigantic in both height and width.
And to put the resolution in a bit of context, the highest resolution digital projector today is 4K.
70MM IMAX has the equivalent of 18K resolution
Seeing the movie without that stunning picture would just be wrong.
Interstellar, The Dark Knight, and The Dark Knight Rises are all acknowledged to be very good movies. But in those cases too, the step down from 70MM IMAX is such a great loss that they as well should only ever be seen in 70MM IMAX.