The trouble is that whilst that is true today, LemonJam, it might not be tomorrow, and if the systems are in place and people are compliant about it, we could be looking at a different picture.
I have no immediate concerns about ID cards, and buy 99% of my shopping electrically - I even use my phone to pay for coffee in a cafe - but I can see that setting things up so that everything we do, say or buy can be scrutinised could be problematic with a change of government, and by then it would be too late to object.
If texts can be read after an application based on reasonable supposition of criminal activity, that's one thing, but I'm not keen on everyone's messages, bank accounts etc being open to scrutiny. It makes me nervous, even though I have nothing to hide.