They're trying to make up their minds.
Also, if the page is close or if the browser crashes, you can find the item again by looking in your list of watched items. How else can you easily make a note of what you're interested in?
Watch something and you can see the watch count increase by 1.
Years ago, I had a program that would tell me iirc how many people were watching something on Ebay. Or it told me something, I don't know what elsse it could have been.
I think that program was lost but might be findable with google.