Circuit Breaker on Ammeter Bypass

basically a fusible link has no "moving parts" so to speak. no places for tarnish to take hold and increase the resistance over time. when the resistance gets to high things melt.

so as long as you maintain the connectors / breaker it will be fine.

if you leave it ignore it you will have a meltdown.

if it's a street driven car with moisture under the hood (rain at times etc) i'd stick with the fusible link. or use a sealed box for the breaker
if it's trailer queen/garage kept never sees rain it wont matter

for what it's worth i've only seen fusible links fail at night when the headlights were in use, usually because the headlight switch is worn out / corroded / needs replacement. switches dont last forever. headlight/brakelight/tail light sockets get cruddy too