This is a debate, not an argument, let’s be adults about this. [Insert political joke]
Sure, but as far as I could find, even those have trip rating of 30mA. But perhaps I could find some with lower rating.
Yes, and 30mA, even at mains voltage, will not kill someone. Static shocks can vary from 1,000V to 500,000V and are usually around 5mA for reference.
In my country the differential switch is mandatory, every circuit must be protected, be it from a main one or separate ones for each circuit. I’d be surprised if it weren’t the same all over the EU.
For new installations in the UK that’s true. But my house, for example was wired in the 1990s and has an RCD only on the sockets (the reasoning I think was that an old style incandescent bulb failing might trip the single RCD taking out the whole house power, but could be wrong).
Since the early 2000’s they changed it for new installs to be RCD for all circuits I believe.