An argument for fuses and maybe power cables in power amplifier

There are a lot of discussion about fuse but I don't remember a thread that include

an actual circuit.

The circuit below is called a rectifier which converts AC voltage from the wall to DC voltage that feeds to audio power amplifier.  All if not most power audio amplifier uses this topology.  Some have bigger transformer, some have more capacitors, some have higher voltage output but most are more or less the same.  Audio amplifer uses a lot of current so they don't use a regular which may even degrade the supply, therefore most will just use what you see below as a rectifier circuit.

You can see from the circuit the current comes from the wall, the AC source far left, to the fuse, F1 5A upper left, go through the transformer then to the diode rectifier, D1 D2 D3 D4, then finally to the 25+/- supply source which then will feed to the power audio amplifier.  

So you can see the fuse is clearly in the signal path.

As for the power cable, it is harder to understand.  Most power cable are already  beefy enough to handle the current so having an even beefier cable will help is something that needs further reasoning.