reasonably certain that all the detail on your film will be captured by the film scanner. Having all those extra pixels to work with offers several advantages. If you have to resize the image (zoom in to loose a boom mike or an airplane that shouldn’t be there) the extra resolution allows you to resize the shot without softening the image or developing scaling artifacts (jagged edges, etc.). 4K also allows you to have the highest quality archive, whether on film or in a digital format. But all this comes at a price. Literally. All those extra pixels require more storage space. Moving all those pixels requires more expensive hardware and software. 4K simply costs more.
Detail of 4K vs. 2K scan. Blowups are taken from the center circle.
It is important to note that a 4K scan does not always guarantee a sharper image. Your choice of lenses has much more