Last time I got stranded by BA when attempting to escape from the US, I had to use three vouchers to pay just for the breakfast in the assigned hotel. (I received dinner, breakfast and lunch vouchers for the 20+ hour wait, so all of them went to just the one "meal".) I think it was USD 12 per voucher, so Finnair's offer is slightly better than that, but still probably not enough for a decent meal at the airport.