I average 18 sts to the inch whip stitching most hexagons together, and yes, you can 'just' see the stitches, but it's quite usual to use thread that blends in and that means the stitching isn't so noticeable. Even on silk using silk thread the stitching does show a little (usually 25st to the inch on that). Your hands find a rhythm and the pieces come together quite quickly.
Thing is though; you show your stitches when you quilt, why should neat and tidy and even hand stitches not be seen on hexagons, or other paper pieced patches, too ?
Mary