The reason I carry one is 1) it will never crash or run out of batteries 2) sometimes while it's nice to have a de-cluttered view excluding roads, rivers, airfields with a runway <500m etc, if you need a quick sanity check that isn't GPS based, at least you have something that shows it all without having to faff about changing config options. They are also useful as a sanity check while planning as it's easy to hide airspace >xxx on some electronic charts and think you are free to fly wherever you want. However, besides what I said once airborne my paper chart is put down the side of the seat and it generally stays there until I tidy the plane up after landing.