.Ra: How many of you don't use the client and why?
I do not use Galaxy. Why would I want to? I try to install as little as possible on my system. Optimally I wouldnt install anything at all and optimally it should be possible to simply copy a game into a directory and it would run then without messing with the system. Unfortunately Windows is misdesigned in that it inevitably gets messed up eventually if too much stuff is installed on it. And this is not possible for most software including games anyway because they require some 'installation'. And with Galaxy I would have to install one more thing. And it would probably mess with the system more than individual games do.
And there are more obvious reasons against Galaxy like privacy.
.Ra: Also do you install one game at a time or multiple?
One, usually.
.Ra: And how do you organize your games if you do have multiple installed at the same time? Pics are welcomed.
Not sure what you mean with 'organize' - they are all in the same directory.