P = I x I X R?It's an advantage because you don't have to replace the fuse. Really, it should never trip and the fuse should never blow unless you get a dead short to ground.
I agree with Joe, the over heating of the fuse holder is due to too much contact resistance in the holder, probably shitty plating. If you have 0.1 ohm of contact resistance and 10 amps going through it that's 10 watts which is plenty to melt a little thing like that after an hour with no way to dissipate the heat.
I dont really remember my electrical engineering classes too well, but I know P = I x E because mmmmm pie....
Comparing a breaker and fuse holder, the breaker definitely looks like it can handle more power without melting.. Does a marine breaker differ much from those ones used for households? Not exactly certain about the availability of a "marine grade" over here where I currently am without ordering it.