Such a bargain

As is proved by the fact that both he and Genie are the only characters with only 4 fingers, instead of 5

Actually, it is a lamp! We just never see it lit, so it might be confusing as to how it works for someone who doesn’t live in ancient times. It’s kind of funny that thousands of people only know the design of ancient lamps because of the Genie, like an accidentally preserved remnant of the past. Anyway, how it works is you would fill it with oil, then put a wick in the spout part. You would light the wick on fire, and it would draw oil until it was all burnt up. That design was used for thousands of years.

thats like saying a ford isnt a car cause you haven't seen it on the road.

Well, you can't have angry customers trying to kill you because their lamp doesn't work.