Can someone explain to me what use does a smartwatch even have? Cause i cant think of one use

[DavidWilliamApp]

I wonder how talking to a watch can possibly be practical? Many are actually saying that it will be wrist worn smartphone! But what about the screen size, memory and the endless possibilities made possible through present day Smartphones, which are actually fully replacing laptops and PCs? I do not see how I will possibly be able to write my mails and play games on a trinket the size of my wrist. Hoping to hear more about this device though!