If item has a motor, requires a 20-amp or greater fuse... consider it high current. So much of our vehicles wasn't fused other than the fusible link outside bulkhead.
They pulled power for a convertible top pump straight off the amp gauge and ran large wires to a very robust manually operated switch with cycling circuit breaker mounted on it. Relays allow for much smaller gauge wiring to lesser switches. The larger high current wires go to relay and pump motor. it's the same principle as your starter relay. Could you imagine battery cables coming to a switch in your dash?