BurntSoul: . The reason why I decided to use it? The main reason was so my installations would automatically update.
Okay, so over time I have acquired a fairly large collection of GOG games, and I would download/archive the installer and install the game. Any games that needed updating meant I would re-download the game, delete the old installer, replace it with the new one and manually update any installed games.
Later on I would log in and see a tag that showed 3 games were updated, (for example). I like to keep everything updated, so I'd go to my library first (never fails, did it every time) and couldn't tell what the changes were until I went to the forums. While the download was 75% done, I'd find out that the update was for a content update, or for the linux version. BackAsswards! Never knew why they didn't implement a changelog at the library...
I get that, but just wanted to point out that a vast majority of that re-downloading was unnecessary. For example, see my screenshot. I had 56 games marked as updated (because I learned some time ago that most of those weren't really updates to the games)
Out of the 56 marked as updated, only 6 had actual changes to the games. 6 out of 56. That meant to keep the games themselves updated, it only required re-downloading about 10% of the time something was marked as updated. Of the rest, 2 were for Linux versions added (no need to re-download if you're not using Linux), 1 was for a language addition (no need to re-download unless that was a language you were interested in) and 1 was for a 32-bit patch (no reason to re-download it unless you're using a 32-bit OS). So that's only 10 of the 56 that even had anything at all in terms of changes. All the rest were (I'm assuming here, so someone may correct me if I'm wrong) simply updates to the installer itself (so that when you're installing the game, the ads you see while it's installing are updated).
But yes, automatic updates is a nifty feature, and I get why people like that. IMO achievements are completely bogus but I also get that to others those are nifty and well liked too, so that's another plus. And for those that like multi-player, those options are very nice to have as well.
I've always understood why folks like clients (speaking particularly about Steam) but Steam could have done it just like GoG did it, and provided all of those "good things" without adding the extra burdensome DRM. Had they made that choice, I wouldn't be such a Steam critic because I do get why folks like some things about clients. I just don't, that's all. But that's just me. But I do applaud GoG for keeping it OPTIONAL, as it should be.