A page and a bit goes by, and my questions go unanswered. Dammit.
The $200 does not cover the developers fees for the respective platform. You will still need to pay these as well.
The biggest benefits for using GMS vs the native SDK's for the individual platforms is rapid development and cross platform execution from a single code base. If you wanted to make a game for Windows, Mac, iOS, Android, and HTML5 without GMS you would have to recreate the game 5 times. On GMS you can use the same code base and deploy to all 5 platforms.
Not to mention, you better know HOW to code for all 5 platforms. Otherwise you are going to spend a LOT of time learning or have to pay someone to port your game to the platforms you cannot program for. Either of these options are going to cost your more than the price of the export modules. (Yes, even learning for free on the internet, because the time you spend learning is down time, and time truly is money unless you have all the time in the world to waste).
If you already know how to use GameMaker, then you already have the knowledge to deploy to all 5 platforms. If you don't already know GameMaker then you only need to learn one tool and language to get your game on all 5 platforms. Not to mention, The Android and iOS modules are the cheapest methods I have seen so far for getting your game on those platforms aside from using the SDK.
Honestly, if your buying GameMaker Studio then you should be buying it as a serious tool to develop games with, and if you are, then $200 is change because you will make that back many times over if you know what your doing.