Two scenarios: You run a ten foot length of wire from the battery to the cab. You mount the fuse at the end of the wire; right next to your equipment. I mount my fuse right next to the battery.

A couple years from now, the wire rubs through the insulation and shorts to ground. The fuse next to the battery blows and you can investigate the cause and replace the fuse when you find the short.

Same wire with a fuse at the far end rubs through. Fuse at the far end offers no protection since there is no excess current going through it. Wire gets hot between the battery and the short. Insulation starts to melt and bursts into flames, fire spreads to other materials. Soon there is a big fire.