What is the significance of the Windows 8.1 start button regression?

In the recent exposure of Windows 8.1, we were very surprised to see the return of the start button, which was confirmed by Tom Warren, a foreign media Verge, after consulting with Microsoft. According to the message that Tom got the message, the start button of the re-return will actually jump to the start screen after clicking. What is the meaning of such a return? Does the consumer really need this start button?

Start The button is a quick start entry for search, shortcuts, and application listings, and apparently Microsoft is not willing to give up the service of the Windows 8 system's start screen, just because of too much sloppy and market pressure to cater to the market. But this does not mean that the start button really returns, all the functions of the start button still rely on the start screen and related Charms.

So what is the difference between the start button and the Win button on the keyboard?