Tahini, interesting uses in recipes

Can anyone explain the difference between tahini and the sesame paste sold in Chinese markets (sometimes labeled “salad dressing”) which is also just sesame seeds ground into a paste?

I bought some a while back, and from what I can tell, tahini is a slightly more runny, and ground slightly finer.

But that seems more like the difference between two brands of peanut butter than anything else.

And one is a lot cheaper…