Your point is moot since you -still- "need" to login to the GoG website to be able to access your games.
If you dont login to your gog account you wont be able to download your game.
I can see what your trying to do, but if you had read previous messages you would see that even with steam "installing" your game, you are not "bound" to keep installing it on steam.
Feel free to copy your installed folder, or zip it and burn it on disc, all you need to do to run the game in the future is drag it off of the disc and voila it works.
The point with GOG is not really moot. Needing to log in to download it is irrelevant, because you already created an account and logged in just to buy it. If you also download it at that point before you log out, then you never need to log in again. In that respect it could be compared to buying a boxed game from an online store. Once it's downloaded, as long as you make proper backup copies, the GOG site could cease to exist, and you could still run the installer on another computer in the future and install it properly. The installer makes no online checks before proceeding.
Now, regarding copying the already installed folder of a Steam game and restoring it to a different PC, yes that will surely work with some games. Since someone has already tried it with CK2, it very well may be true for all the Paradox games. However, that does constitute a workaround rather than installing something the normal way. Steam doesn't allow you to install the game normally without a logged in account, so by copying the files manually you are bypassing that obstacle, whereas GOG will allow you to actually run the installer normally without a logged in account.
Besides, I was referring to games on Steam in general, not just Paradox games. It's definitely NOT true that you can use this folder copying method with ALL games on Steam. Many of them have a modified main executable that talks to Steam to check for the presence of a logged in Steam account, or that Steam is in a properly authorized offline mode. Also, even for games that don't do that, for some of them you may need to save various registry keys or files outside the main game folder, such as in the system folder or elsewhere, so it may not be as simple as just copying the main game folder.
However, since it apparently is that simple for the Paradox-developed games, I'll concede that my overall point was partially moot, in the sense that those are the games we're primarily concerned with here.
It's still a workaround rather than a supported feature, and not one that would work for many of the other games one might buy on Steam.
Edit: The ability to copy the folder apparently doesn't even extend to all of the Paradox-published games from other developers. I just did a test with War of the Roses, and the executable for that game is one of those that has been modified, since it automatically starts up Steam and logs in to the account upon running it.
Further Edit: WotR was a bad example, since that one is already openly professed to be Steamworks. For a good example of what I mean, I'll have refer to a non-Paradox game based on what I have installed at the moment. Rome: Total War is not a Steamworks game, but if you try to run the Steam version without Steam installed and running, you'll just get "Failed to find Steam" instead of a working game. There's no copying of the folder for that one.
