Actually here's the wierd thing. First answer this question for yourself, you dont need to post it, just think about it and then give a honest answer: If you had the choice, would you rather have all your games in one location on a digital distribution platform (with all the potential problems that could lead to) or would you prefer just going to the store, buying a box and owning that box and the game until the end of time?
Steam is essentially a necessary evil at this point. Why you may wonder? Well since it becomes increasingly common that games require either steam or some other digital distribution/DRM method, then there is nothing to be done about it other than not buying whatever game requires it. But yet why is steam more popular than the other alternatives?
Simple, the lesser of many evils (we got more than 2 digital distribution platforms). If you are forced to have one of them, and for the sake of the example i shall use 3, Uplay, Origin and Steam. Which would you pick? You have to have one, so you cant say "neither", but you can pick one out of those 3, which would you take? The answer is probably always going to be steam, why? Because here's what Steam offers that effectively sets it apart from the other 2 choices. Origin sells mainly EA games, Uplay sells mainly Ubisoft games. Steam sells a ton of games, from both those companies and many others.
Just for the sake of convinience, Steam wins because you can buy more games over it than any other service currently available. Add to that daily, mid-week and weekend sales, along with summer and christmas sales which basicly reduce either one, several or the giant catalog of games in price up to 75%. Also Steam/Valve has a habit of treating you fairly for the most part, while it is DRM, it at least offers something in return, namely good sales all year and community features.
Of course there are more services available, say for example GOG. But while they do not "include DRM" so to speak, is that service not also a form of DRM? In the end, do they not also verify that you bought the game from them? Granted, they do not use invasive measures for it, no always-online, starforce or somesuch, but when you get down to it, its all DRM. DRM starts already when you get the reciept from buying a boxed copy. It is proof that you legally purchased the game. So in the end, GOG is about the same as Steam, its a distributor that verifies through your purchase that you purchased it, but does nothing beyond that. Since alot of steam games do not require you to even be active in steam, other than register through it, much the same as GOG does, you cant get a game from them without paying them for it first, which is basicly the same thing.
Its why Steam and GOG are popular, its DRM, but its the least annoying one possible. You dont have to jump through several hoops for them and you arent really at risk of suddenly losing access to all your games. There is a risk but its at least minimal.