The shutter prevents someone (including children) shoving something metal into the live/hot. I have never heard of it failing. Newer US outlets (TR/tamper resistant) are way more finicky because of the optional ground pin. Sticking the little plastic covers over the outlet is a workaround.
The reason for a fuse is because of the high current capacity of ring circuits vs branch/radial. The fuse protects the power cable of appliances catching fire as they can’t handle the current available on the circuit .
Ring circuits are a thing due to minimizing copper usage when rebuilding after ww2.
TR: I know why they did it, but I'm not a fan of the tradeoff. I don't think making all the sockets worse is the solution, people with kids can just baby proof their place (I have a toddler, and we baby proofed our house).
Fuse: I'm not familiar with ring circuits and everything you mentioned, though I was aware it's for fires. Other places (and the UK as well in most apartments I had) have centralized fuse boxes. Is this still needed?
Either way, these are reasons for why things were done the way they were done, but reasons aside, the usability is inferior.
They still have a centralised box but each connection goes in a ring from the box and back to it again. This way you can use thinner wire for the same total capacity.
Sadly it carried on for far too long, my house built in the nineties has it.
UK central fuse boxes don't have a fuse/RCD per socket. For example, mine has common ones for the kitchen, downstairs sockets, upstairs sockets, and all lighting -separate ones only for the boiler and cooker.
The wiring system was designed during world war II when there was a copper shortage and someone calculated that it used less to use larger conductors to several sockets than to run smaller individual ones to each socket.
TR in the US makes sockets harder to use, but I have never heard anyone complain about TR in the UK, as the earth/ground pin is always present, and is physically longer than the live and neutral, so mechanically it is reliable and unnoticeable.
“Just baby proof” means remembering to keep those little plastic covers in place in every outlet. That doesn’t seem like superior usability.
> The shutter prevents someone (including children) shoving something metal into the live/hot.
Child protected schuko sockets exist and work just fine. We have them installed in our place and I never had an issue with them. Neither do things fall out, nor can you poke at them with a screwdriver.