I would guess that both outlets are managed by the same company, and they're probably happy to let customers do that.

The demand is dwindling, as you say. Smokers and vapers were greatly outnumbered by non-smokers when I looked around Cafe Noball. It reminded me of the situation on Chuo line express trains in the mid '90s - Reserved seats in non-smoking cars often sold out, while smoking cars invariably had seats to spare. I even knew smokers who didn't want to be in those cars. For now, the airport feels that it can't risk upsetting smokers by denying them an indoor space to smoke and eat, but it's fine to have employees in a smoky environment. I expect it will soon change.