Why are product images shown along with coins

 I wondered how come no one has written about it? Is the answer so basic that it doesnt need any explanation?. I assumed may be they are showing the coin as an indication for the cost of the product for few days.

At last i pinged my friend and senior on skype and asked , Do you know why coins are shown along side with product images of electronics components?.

He said , “Yes, because we all know the size of coins and they are shown as an indication of relative size of the product or (chip or connector) compared to that coin” . 

It was indeed very basic and i didn’t think about it, may be that’s why no one has written about it. How dumb of me ;). But i was wondering, all the coins shown are US dollars. Problem is i never held a quarter dollar coin in my hand. How would i know the size of the product based on that image. May be those images are helpful for US buyers. I suggest they start using other country coins too. 🙂