Split lock washers do nothing?

Split washers are not the best for resisting fasteners coming loose. They are not used in modern aviation where vibration has a great effect on parts coming loose. Lock wire, cotter pin, locktight, nyloc nut ect. is used when you need it guaranteed not to come loose. The shelving in your garage is one thing, something coming apart going through air or on the road is something else. Spindle nut, cotter pinned. Crank and rod bolts, locktight. Proper torqe will hold most things together with no worries. If worried, would not use split washer.