Small angling boats are a big market particularly in the USA so many of the cheaper devices are aimed at them: volume sales helps reduce price. Often a combined sonar/plotter is cheaper than a plotter only.
You might not fish, but having a picture view of the bottom and how it is changing is mighty useful, well I think so anyway. A modern chart plotter can show you a full chart screen or be split. You don't have to display the fish finder screen if you don't want to.