That doesn't make sense -- the lower deck of the observation car is the cafe, which is the main (effectively only) place to get food, coffee, etc. when you're in coach, since the dining car is reservation only and you're behind everyone in a room.
The observation car is open to all passengers, no exceptions. The Dining Car is still sleeper-car only, although they seem to want to change it back to taking paid seating from coach/business some time this year.