That's hardly special. I've stored lettuce that I bought commercially for 4 weeks and it was fine. So that's 4 weeks plus however long it took to get to me. (I bought too much by mistake.)
Then it sounds like better preservation would be expected. The article says it lasts two weeks at 10°C. I have no idea how exceptional that is as I've never knowingly stored lettuce at 10°C, but it probably doesn't last as long as lettuce as refrigerator temperatures.
