My theory is that the cup is regular on the inside and the bottom is weighted to provide stability. It's raktajino. It's Klingon. So if a spontaneous heroic fight erupts around you, you want to
Use the cup as a weapon
Swipe the cup out of the way for the battle without it toppling over so you can then use it to toast on your glorious victory in the battle of the breakfast.
Fun fact: these were actually real cups you could buy (they picked them because of how weird they were), so there are likely unsuspecting people out there using them still today. They don't know that they're prepared for a battle at any moment.
Yep. I laughed when one of those showed up like it was the cup of the future when I literally used one every day during my morning commute in the 20th century.
I think a good head cannon for this is that a mug is such a basic thing that you don't really need to keep re-inventing a new design from scratch. So when a new replicator system/technology comes out, you just port stuff over from the old one. Like maybe it's one of those patterns in the replicator database that just goes back eons to united earth or something.
The cup is bottom-heavy and usually has a high friction substance on the bottom so that it's less likely to spill when you take an unexpected wave on Earth, or an unexpected photon torpedo on DS9.
E2a: You can google Feltman Langer or no-spill mug.
Yeah I always thought it was kinda funny that this became "the raktajino cup" when I always took the cup's shape to be a symbol of how DS9 was this ramshackle station "on the frontier". I mean it makes sense that Klingons would want a mug that can resist spillage but when DS9 first aired I never thought it was anything beyond just a robust mug.
That style of mug became popular in the 80s, when corporate commuting and cubicle culture exploded, and cars didn't all come standard with cupholders yet. A mug like this could sit on the dash or console with stability, and it was also good for a crowded desk because you couldn't knock it over and spill it.
I'd have thought that the cylinder part was hallow. But the bottom part was solid. Thus. Seperate your hot beverage from your surface - be it table, hand, lap. No need to hold on to it if it's not hot on the bottom.
You laugh, but you'll wish you had one of these when you lose your inertial stabilizers! You'll go flying through the bridge viewscreen, but that mug will sit there watching it happen.