Let me tell you a story:
Once upon a time there was a beautiful princes, and she...
Oh wait, that's the wrong story.
I used to tour back in the 1960s. That was the era of two-wire power cords. Once the stage was set up and the PA in place, we powered up and went around the stage flipping the ground switches back and forth to get the hum to a minimum and hopefully reduce the shock potential. Usually we got it pretty well set. One night, my guitarist was playing a solo, and he raised the guitar up while bending a note, and the strings touched the microphone. A flash of light, and the high E string burnt in two. Just burnt the string in half. Chris was OK, but he had to finish the set as a five-string. Fortunately he hadn't yet put his lips to the mic.
Your house may have no wiring issues, and your amp may be good as well. But you can't guarantee those conditions everywhere. You will play gigs that have no grounds, or the outlets are wired with the wires wrong. The stage might be OK, but the PA system is on a different ground. Exactly what happened to my guitarist. If you are holding your strings, you are connected to whatever your amplifier thinks is ground. If the PA system thinks something else is ground, there might be a large voltage difference between the microphone and your strings - and your body is the connection between them.
If a fuse opens the connection to your strings, then the PA can't make a circuit to your amp. If that fuse opens, your strings are no longer grounded, so the amplifier will likely make more noise, but that is the price you pay for safety. Your hands only touch the (now ungrounded) strings, so touching the PA makes no circuit.
How effective a 10ma fuse is, I can't say, and people who know anything about guitars probably have more insight than I do, guitars are not my area. But that is my take on it.