>The second one is only confusing because you're trying to find a cause and effect between 2 events that simply happened to happen at the same time
The author uses "because", which in context clearly indicates to me a cause and effect relationship.
Even overlooking that, "impecunious operation of the bank could cause the value of the mortgages to be impaired" is not addressed by your explanation. You explain how external factors could reduce the value of the mortgages.
You have a point, and I think there is a bit missing. Currently it says:
... impecunious operation of the bank could cause the value of the mortgages to be impaired just a tiny little bit at a time when people need most of the money in their checking accounts.
And probably should say something like:
... impecunious operation of the bank could cause trouble if the value of the mortgages is impaired just a tiny little bit at a time when people need most of the money in their checking accounts.
The author uses "because", which in context clearly indicates to me a cause and effect relationship.
Even overlooking that, "impecunious operation of the bank could cause the value of the mortgages to be impaired" is not addressed by your explanation. You explain how external factors could reduce the value of the mortgages.