Re: This requirement for paper bills/statements...
This is the primary difference between the British legal system and a lot of the Continental ones (mostly derived from the Napoleonic Code).
In the British code, anything not specifically made illegal is legal.
There is no such thing as "the British legal system" or "the British code".
Scotland, Northern Ireland, and England & Wales (together) each have their own legal system - three in all.
I don't know about NI, but I do know that Scots Law was historically based, in common with many of the legal systems in contentental Europe, on Roman law. England, of course, had to be different, and evolved its own "common law".
IANAL, but my Mum - who wasn't either, but did work in a legal office in Scotland - once explained to me that court cases in the English system tend to be very adverserial - ie very much one side versus the other - whereas the approach in Scottish courts, although of course having two sides, is more to try to establish the truth, or what happened, and so arrive at a verdict that way.
Scottish courts also see no one as being above the law, see everything as within their remit, and really do try to see fair play, as evidenced by the two recent cases against the government, one saying "of course they misled the Queen into suspending Parliament", and the other, ongoing, in which they are ready to jump on Johnson if he doesn't write the letter requesting a Brexit extension (if it is required).
English law and English Courts, in contrast, are a f***ing mess :)