Hopefully, the beginner will ascend to journeyman and eventually Grand Master status and may find the declination adjustment useful. In most of the country where I roam, the declination is about 15 degrees or so, but if I travel to the Pacific Northwest, I might want to tweak it a bit. It is just a nice feature that renders the compass a bit more versatile.

On my Suunto, the declination scale also serves a a clinometer, which can be extremely valuable in some situations.

One always has the option of simply navigating by magnetic north. With marine charts, where magnetic north is clearly indicated, that is often the best course to follow.....