It looks like you're new here. If you want to get involved, click one of these buttons!
1) Windows will now be compressed on SSDs, greatly reducing the installation size and making a 32 GB tablet not a complete joke for lack of storage space after the OS takes it all.
2) Windows will be more aggressive about suspending idle applications, allowing it to run only 1 GB of memory, at least if you don't like to run much in the way of other software besides the OS.
3) Windows will now be free on devices with a screen size less than 9".
The first two are largely about allowing Windows to run on lower end devices. Do you really want a tablet with 32 GB of storage space and 1 GB of system memory? The former might be okay for some purposes with a slimmed down installation size. But some software wants more than 1 GB just for one application. Even if you don't expect to play AAA MMORPGs on a tablet, browsers commonly want several hundred MB--and web browsing is one of the core things that you're supposed to be able to do on a tablet.
But the last one is the biggest deal, I think. Microsoft doesn't charge $100 to OEMs for Windows; I think it's somewhere in the ballpark of $30-$50, though I didn't just look it up. But after various other companies along the way take their markup, eliminating the cost of Windows might well subtract $50 or $70 or some such from the price of devices.
Barely any Windows devices sell with a screen size below 9"; Android has most of the market for such devices (both tablets and phones), and iOS has most of the rest. So it's not like Microsoft is giving up much revenue to do that. Laptops virtually never have a screen that small, and Windows is still the dominant OS in that form factor.
But this is obviously driven by competition. What happens if laptops running Android or iOS become popular? Or, for that matter, Chrome?
There is one caveat on the "free Windows" bit, but it's a small one: the OEM has to make Bing the default search engine for Internet Explorer. End users are, of course, free to switch to a different search engine--or better yet, a different browser entirely.
I've often said, if you want a Windows tablet, you should get such and such hardware. But that assumes that you actually want a Windows tablet; most people don't. As the article linked above said, in tablets and phones, Android isn't viewed as a low cost, inferior alternative to Windows. Microsoft is trying to make Windows more competitive, and that's a good thing.