Both the reading and the the lecture discuss about the curved stone and it is purposes. The reading says some theories regarding these curved stone. But, the lecture refutes all theories made by the statements.
First of all, the reading states that they might used it for weapon because it has the groove which allows the cord attached on it and swing easily to throw it. However, The lecture counter this view by saying that earlier people used the arrows and spear as a weapon and that has more advantages than this curved stone. So, it was not useful for them. Moreover, most of the stones are cracked and only the surface of stone preserved, so, it looks like weapon.
Secondly, the reading states that it might be used as primitive system of weighing and measuring because all the stone are same 70 mm diameter, it suggested that they used for trading. But, the professor opposes this point by stating that even though it is same size, their mass is varying from one stone to another due to different material they used to make it. Further, some are heavier and others feather weight, just like bird feather. So, it was not used for primitive system measurement.
Finally, reading claims that it may be used as social purposes because of it's elaborated design such high status in the society. Still, the speaker reputes this idea by explaining that they design were very simple. Plus, usually they use to burial the valuable possessions after the death but they did not anything like that in tombs or graves. So, it is highly impossible that they used the curved stone as a social symbol and status.
To sum up, the reading states that because it has groove, uniform size and elaborated designs- they might used as weapon, weighing and symbol social status. But, the professor refutes all these points with strong evidences.