Floor jack cup - what the hell?

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Consider this a newbie question.

I have a cheapish floor jack very similar to this
http://cimg3.ibsrv.net/cimg/www.doityourself.com/6...

Is has a nasty cup type thing as the actual lifting point.

I’ve seen a lot of floor jacks [more expensive ones] which are just flat.

What is the purpose of the cup style?

I used it yesterday with a hockey puck on top, it worked ok but the puck din’t look right sitting on top of an uneven cup.

Please tell me this cup is for delivery purposes only or something like that.