Circuit Breaker vs Maxi Fuse

continuous duty
see here: questions about battery disconnect wiring

As far maxi fuses vs. links.
The main purpose was to prevent the battery from massively discharging when shorted to ground.
You know there's enough juice in there to arc weld!

Size protection for the weakest link downstream.
The fusible link can tolerate short periods of somewhat high current. This is a trade-off of providing protection against major overloads while limiting the chances of disabling the vehicle for minor overloads.