Is that fuse in the only power path to the engine critical bus?  I think fuses are a very reliable way to go; but for this application they are synonymous with “fault tolerance”.  IOW, blowing one fuse does not shut you down.  Actually, I would also apply the fault tolerance idea to the use of breakers for critical items.

One of the nice things about our setup is we have dual plugs, dual injectors, dual controllers, and dual fuel pump. That gives you the potential for very high reliability - a failure of any one of the pair does not put you on the ground.  I chose to use a separate circuit to each to gain failure tolerance. Each circuit is protected with a fuse, and the fuse holder is powered directly from both batteries with isolation diodes so even a battery failure doesn’t stop the engine.

Wires are cheap and light and very reliable. Fuses cost only pennies, so change them out and check the contacts every annual, or every 6 months if you feel like it. I like that better than a breaker that has been in the panel for 10 years. Fault tolerance = high reliability. (I almost said – fuses and fault tolerance, but I don’t want to start that fuses vs breakers discussion againJ)

FWIW,

Al