I believe Collector's point is that they didn't actually make the games compatible. They're just passing out DOSbox with it. You can use DOSbox to play the games on XP/Vista but using emulation doesn't equal compatibility.
In some ways this is better than to rework the games. The DOS games will always be compatible with a DOS emulator. A game patched to run on modern Windows may only be compatible till the next version of Windows. In addition, with DOSBox you don't need GOG if you already have the game. The concept of GOG is good if you do not already own these games.