Bokeh is the effect of blurring out the background. Its important because it lets you isolated the subject, like a human face, from the background.
Still, if it does one thing better than other lenses, it will be useful.
Bokeh is the effect of blurring out the background.
In other words, bokeh is fundamentally an aesthetic characteristic.
here's an extremely in depth look at what that means.
It explains what people mean by "soft bokeh" (~= bokehlicious!), apodized lenses, and the "cat's eye" shit you find sometimes.
In that case, we truly woulnd't miss it.
Depth of field is incredibly important for managing a viewers focus. Imagine a picture of a coffee in a coffeeshop with the background out of focus - you can clearly see a coffee cup. That same photo but with everything in focus will be much more confusing - what should I be looking at, it's too busy, etc.