In fairness, for all you are supposed to isolate, explain reason, take name, show card and then warn as to future conduct, no one really cares about the 2nd and 5th of those activities. What they don't want is flashing of cards, as it has led to issues with ARs recording the wrong number and then not getting involved when the referee cautions again and doesn't send off. Fine at higher levels as they can ask the number over comms, but I've been on the line before when I haven't had a scooby who the referee has cautioned. Indeed, I observed one L4 and I honestly was clueless to who he was cautioning as he was flashing the card in the general direction of a pocket of players.
And taking the name is because team sheets at grass roots, and even at some higher levels, are notoriously inaccurate. They are often filled in by the manager or captain at the side of the pitch, he can't put the shirt numbers down until everyone has arrived and is dressed, and therefore relying on this information to submit misconduct is always likely to be risky. I've seen it whilst waiting for it to be finished, "Oi Dave, what number are you wearing", "7 I think, wasn't really looking". I was at L4 and L3 before the new rules came in, I did flash cards as it was allowed then, and I know that things went wrong as I was contacted by discipline departments on several occasions to clarify who I had cautioned. I think what tipped it is one L3 referee reported 9 cautions and every single one was challenged by both clubs as being wrong, the thinking is he used the home numbers for the away team sheet and vice versa, so they said enough is enough and you have to take names.