Question: I am a junior developer I can't understand how canvas tag is beneficial for us?
I read lot of articles on that but I can't get the root benefit getting from the canvas tag.

Answer: 
Basically, thanks to canvas, we can now draw/render 2D shapes using HTML5 and the canvas API.

As an example of what's possible now with canvas, [see this](http://muro.deviantart.com/)
my personal take on canvas (and when I actually found a use case for canvas) is the ability to color pick and color change per pixel in a canvas element - actually moving the image from something we don't have any information about what is happening inside it to an element like all other DOM elements (and yes, I know about the current problems with canvas and DOM - sure this would be taken care of in the future)

sure - canvas made some sort of animation easier and pluginless, but that we could do before (mostly with flash) - I think the real importance is the ability to know what is happening on the page.