OSG Standard Circuits - 3A lighting

What advantage would there be of using a 3A MCB? I can see none at all, and just a pile of possible snags. Close fusing may be used in certain other situations, but why on a simple lighting circuit? Just who floated the idea, because it needs a proper explanation? Perhaps it's the latest EU idea to save energy, turn on 3 lights and the whole lot go out. Even less sensible than a 500W kettle! Whilst a 3A type C might work Mike, please explain the advantage and the price differential? But then they might get cheaper in the future, like AFDDs. Ah I know, a 3A AFDD/MCB/RCD combination will mean the AFDD doesn't have to work at all, pretty much as they don't if the arc is low current < 3A! Still in the regs though.

What advantage would there be of using a 3A MCB? I can see none at all, and just a pile of possible snags. Close fusing may be used in certain other situations, but why on a simple lighting circuit? Just who floated the idea, because it needs a proper explanation? Perhaps it's the latest EU idea to save energy, turn on 3 lights and the whole lot go out. Even less sensible than a 500W kettle! Whilst a 3A type C might work Mike, please explain the advantage and the price differential? But then they might get cheaper in the future, like AFDDs. Ah I know, a 3A AFDD/MCB/RCD combination will mean the AFDD doesn't have to work at all, pretty much as they don't if the arc is low current < 3A! Still in the regs though.