Re: National Identity Card
"You can use the card to sign an electronic document in a legally binding way, for example. That's in itself is something many people might find very useful."
Not really in Britain, it's not. Documents "signed" by email or using e-signatures are already legally binding (in almost all cases - there are certainly some exceptions).
I don't know anything about Estonian law but I assume (!) it's a civil law country in which notaries public are used to record/formalise contracts, leases etc fairly regularly. If the electronic ID card replaces that need and they already have a mandatory ID card system - well, great, I suppose.
But in the UK, ID cards and electronic voting are solutions looking for a problem. We got on fine without them. Paper voting is cheap, easy and works pretty well. It's no surprise that the biggest proponents are like Malloch-Brown, who sells the machines!