If you want to do away with the tedious chore of actually looking for something cool to play, Steam is the best way to deal with game purchases.
The Game Store
The main function of Steam is, naturally, the largest digital game store in existence. You can browse the categories or look for something popular, new, or otherwise noteworthy. there are discounts, official releases of AAA products or indie developments. The convenience of game updates and patches downloadable and installed in a single click is something even the pickiest user would find convenient.
Social Platform
But it's not just the gaming experience that the actual gaming is all about now, is it? The ability to share it all with friends, find new people to talk about games with, researching user feedback or reading the news - all of that is possible on Steam. Reviews, guides, walkthroughs, troubleshooting, and just about anything you might want is accessible from the Steam client. Special mention goes to the Workshop, where you can download modifications and unofficial patches.
Summary
Steam is trying to be the one gaming client to rule them all, and, if we're being honest, it's succeeding so far.