They are mostly talking about the physical makeup of money, inflation and, whether one of their friends in the 1970s would have purchased a beer or cannabis resin with extra money. Some examples (although I don't want to get bogged down in this specific instance; I'm more interested in flagging practice generally):
In the 1970s a friend washed, in a launderette, a pair of jeans with a one-pound note in a pocket. It was real money in those days for a young student. Worth around 12 US dollars in today's values. He sent it to the Bank of England and they mailed him a £1 postal order to cash at a post office.
I don't know where you got that from, but around here, nobody but car dealers and jewelers regularly come in contact with 200 euro bills. Most transactions requiring bills that size are now made electronically. Lots of shops will not accept 500 and 200 bills.
in fact knowing this guy he would have spent £1 of fun money on cannabis resin, and it would have got him around 2 or 3 grams, and you can't really buy that stuff these days. I don't know what £10 would buy now, as I don't use recreational drugs
Can a person who reviews such flags explain how the comments are helpful so that I can be more selective in my flagging (if you even mind that I have over-flagged in this instance)? Or, if it's alright that I might be raising flags that sometimes are declined, let me know that too (i.e. I should just keep flagging as I see it and you'll just decline what you disagree with and that's all fine - I found this other answer after writing this question). I just don't want to be cluttering your queues.
I appreciate any insight into how moderators approach these. To be clear, I am not critical of the approach taken by moderators to these particular flags; it just doesn't match my prior understanding, and am looking for understanding of how the moderators view things to help guide my own flagging behaviour. Hopefully this is also helpful to others.